Files
nexus/sreweekly/articles/443/07-heterogeneous-sli-vs-homogeneous-sli.html
2026-09-12 17:23:01 +08:00

492 lines
194 KiB
HTML
Raw Blame History

This file contains invisible Unicode characters
This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8" />
<meta name="norton-safeweb-site-verification" content="24usqpep0ejc5w6hod3dulxwciwp0djs6c6ufp96av3t4whuxovj72wfkdjxu82yacb7430qjm8adbd5ezlt4592dq4zrvadcn9j9n-0btgdzpiojfzno16-fnsnu7xd" />
<link rel="preconnect" href="https://substackcdn.com" />
<title data-rh="true">Heterogeneous SLI vs Homogeneous SLI - Alex Ewerlöf Notes</title>
<meta data-rh="true" name="theme-color" content="#001426"/><meta data-rh="true" property="og:type" content="article"/><meta data-rh="true" property="og:title" content="Heterogeneous SLI vs Homogeneous SLI"/><meta data-rh="true" name="twitter:title" content="Heterogeneous SLI vs Homogeneous SLI"/><meta data-rh="true" name="description" content="This article defines Heterogeneous and Homogeneous SLIs with examples, illustrations and their pros and cons. It then concludes with a lightweight guide on when to use which one."/><meta data-rh="true" property="og:description" content="Cons and pros of each approach and when to use which"/><meta data-rh="true" name="twitter:description" content="Cons and pros of each approach and when to use which"/><meta data-rh="true" property="og:image" content="https://substackcdn.com/image/fetch/$s_!aFXH!,w_1200,h_675,c_fill,f_jpg,q_auto:good,fl_progressive:steep,g_auto/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png"/><meta data-rh="true" name="twitter:image" content="https://substackcdn.com/image/fetch/$s_!9m6k!,f_auto,q_auto:best,fl_progressive:steep/https%3A%2F%2Falexewerlof.substack.com%2Fapi%2Fv1%2Fpost_preview%2F148798453%2Ftwitter.jpg%3Fversion%3D4"/><meta data-rh="true" name="twitter:card" content="summary_large_image"/><meta data-rh="true" property="article:modified_time" content="2024-09-26T20:07:15.277Z"/>
<style>
@layer legacy, pencraftReset, pencraft;
</style>
<link rel="preload" as="style" href="https://substackcdn.com/bundle/theme/main.06a4c4c291d4583811c7.css" />
<link rel="preload" as="font" href="https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaFF31CPDaYKfF.woff2" crossorigin />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/11100.cee9fbee.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/86118.c25b9f67.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/93519.6640a5b2.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/42118.cba90b72.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/39522.25128f14.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/47358.668d8a3c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/94881.cb76fe04.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/27386.72f00430.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/76768.f15fc605.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/41932.97d2663c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/48409.0588981c.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/32552.313415d5.css" />
<link rel="stylesheet" type="text/css" href="https://substackcdn.com/bundle/static/css/27313.92c631cb.css" />
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=0, viewport-fit=cover" />
<meta name="author" content="Alex Ewerlöf" />
<meta property="og:url" content="https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous" />
<link rel="canonical" href="https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous" />
<meta name="google-site-verification" content="HIy4u2xUDZkIs6P0KJw9TSYeq7KqXSPAQvZIs9911qU" />
<link rel="shortcut icon" href="https://substackcdn.com/image/fetch/$s_!j4nj!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon.ico">
<link rel="icon" type="image/png" sizes="16x16" href="https://substackcdn.com/image/fetch/$s_!VSMg!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-16x16.png">
<link rel="icon" type="image/png" sizes="32x32" href="https://substackcdn.com/image/fetch/$s_!CJdc!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-32x32.png">
<link rel="icon" type="image/png" sizes="48x48" href="https://substackcdn.com/image/fetch/$s_!5Qve!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Ffavicon-48x48.png">
<link rel="apple-touch-icon" sizes="57x57" href="https://substackcdn.com/image/fetch/$s_!gV2k!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-57x57.png">
<link rel="apple-touch-icon" sizes="60x60" href="https://substackcdn.com/image/fetch/$s_!L4Uu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-60x60.png">
<link rel="apple-touch-icon" sizes="72x72" href="https://substackcdn.com/image/fetch/$s_!X3nD!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-72x72.png">
<link rel="apple-touch-icon" sizes="76x76" href="https://substackcdn.com/image/fetch/$s_!Xe9B!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-76x76.png">
<link rel="apple-touch-icon" sizes="114x114" href="https://substackcdn.com/image/fetch/$s_!ef9e!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-114x114.png">
<link rel="apple-touch-icon" sizes="120x120" href="https://substackcdn.com/image/fetch/$s_!B-Gw!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-120x120.png">
<link rel="apple-touch-icon" sizes="144x144" href="https://substackcdn.com/image/fetch/$s_!PA8p!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-144x144.png">
<link rel="apple-touch-icon" sizes="152x152" href="https://substackcdn.com/image/fetch/$s_!x3Pg!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-152x152.png">
<link rel="apple-touch-icon" sizes="167x167" href="https://substackcdn.com/image/fetch/$s_!7ISu!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-167x167.png">
<link rel="apple-touch-icon" sizes="180x180" href="https://substackcdn.com/image/fetch/$s_!k1Y3!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-180x180.png">
<link rel="apple-touch-icon" sizes="1024x1024" href="https://substackcdn.com/image/fetch/$s_!hatU!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fa0c1d559-cfc9-48dc-9e78-57b4c52d5b70%2Fapple-touch-icon-1024x1024.png">
<link rel="alternate" type="application/rss+xml" href="/feed?sectionId=67723" title="Alex Ewerlöf Notes"/>
<style>
@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG36AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG3zAvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG34AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG35AvH4ZL_Ean2DTA.woff2) format('woff2');unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:'Merriweather';font-style:italic;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4B0qyriQwlOrhSvowK_l5-eTxCVx0ZbwLvKH2Gk9hLmp0v5yA-xXPqCzLvPee1XYk_XSf-FmTCUG33AvH4ZL_Ean0.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaGV31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0460-052F,U+1C80-1C8A,U+20B4,U+2DE0-2DFF,U+A640-A69F,U+FE2E-FE2F}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaEF31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0301,U+0400-045F,U+0490-0491,U+04B0-04B1,U+2116}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaG131CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0102-0103,U+0110-0111,U+0128-0129,U+0168-0169,U+01A0-01A1,U+01AF-01B0,U+0300-0301,U+0303-0304,U+0308-0309,U+0323,U+0329,U+1EA0-1EF9,U+20AB}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaGl31CPDaYKfFQn0.woff2) format('woff2');unicode-range:U+0100-02BA,U+02BD-02C5,U+02C7-02CC,U+02CE-02D7,U+02DD-02FF,U+0304,U+0308,U+0329,U+1D00-1DBF,U+1E00-1E9F,U+1EF2-1EFF,U+2020,U+20A0-20AB,U+20AD-20C0,U+2113,U+2C60-2C7F,U+A720-A7FF}@font-face{font-family:'Merriweather';font-style:normal;font-weight:400;font-display:fallback;src:url(https://fonts.gstatic.com/s/merriweather/v33/u-4D0qyriQwlOrhSvowK_l5UcA6zuSYEqOzpPe3HOZJ5eX1WtLaQwmYiScCmDxhtNOKl8yDr3icaFF31CPDaYKfF.woff2) format('woff2');unicode-range:U+0000-00FF,U+0131,U+0152-0153,U+02BB-02BC,U+02C6,U+02DA,U+02DC,U+0304,U+0308,U+0329,U+2000-206F,U+20AC,U+2122,U+2191,U+2193,U+2212,U+2215,U+FEFF,U+FFFD}
</style>
<style data-pub-theme-prefix>:root{--color_theme_bg_pop:#FFBC52;--background_pop:#FFBC52;--color_theme_bg_web:#001426;--cover_bg_color:#001426;--cover_bg_color_secondary:#0f2233;--background_pop_darken:#ffb238;--print_on_pop:#ffffff;--color_theme_bg_pop_darken:#ffb238;--color_theme_print_on_pop:#ffffff;--color_theme_bg_pop_20:rgba(255, 188, 82, 0.2);--color_theme_bg_pop_30:rgba(255, 188, 82, 0.3);--print_pop:#ffbc52;--color_theme_accent:#ffbc52;--cover_print_primary:#ffffff;--cover_print_secondary:#d9d9d9;--cover_print_tertiary:#d9d9d9;--cover_border_color:#ffffff;--font_family_headings_preset:'SF Pro Display', -apple-system, system-ui, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';--font_weight_headings_preset:900;--font_family_body_preset:Merriweather,sans-serif;--font_weight_body_preset:400;--font_preset_heading:sans;--font_preset_body:fancy_serif;--home_hero:feature-media;--home_posts:custom;--home_show_top_posts:true;--web_bg_color:#001426;--background_contrast_1:#0f2233;--background_contrast_2:#223443;--background_contrast_3:#485663;--background_contrast_4:#6d7882;--background_contrast_5:#aeb5ba;--color_theme_bg_contrast_1:#0f2233;--color_theme_bg_contrast_2:#223443;--color_theme_bg_contrast_3:#485663;--color_theme_bg_contrast_4:#6d7882;--color_theme_bg_contrast_5:#aeb5ba;--color_theme_bg_elevated:#0f2233;--color_theme_bg_elevated_secondary:#223443;--color_theme_bg_elevated_tertiary:#485663;--color_theme_detail:#192b3c;--background_contrast_pop:rgba(255, 188, 82, 0.4);--color_theme_bg_contrast_pop:rgba(255, 188, 82, 0.4);--theme_bg_is_dark:1;--print_on_web_bg_color:hsl(208.4210526315789, 25.00000000000006%, 90.74509803921569%);--print_secondary_on_web_bg_color:#99a1a8;--footer_bg_color:#000C17;--footer_bg_color_h:208.69565217391306;--footer_bg_color_s:100%;--footer_bg_color_l:4.509803921568627%;--print_on_footer_bg_color:hsl(208.69565217391306, 25.000000000000057%, 90.45098039215686%);--print_secondary_on_footer_bg_color:#999ea2;--footer_bg_contrast_1:#0f1b25;--footer_bg_contrast_2:#222d36;--footer_bg_contrast_3:#485158;--footer_bg_contrast_4:#6d737a;--footer_bg_elevated:#0f1b25;--footer_bg_elevated_secondary:#222d36;--footer_bg_elevated_tertiary:#485158;--footer_detail_color:#19242e;--background_pop_rgb:255, 188, 82;--color_theme_bg_pop_rgb:255, 188, 82;--color_theme_accent_rgb:255, 188, 82;}</style>
<link rel="stylesheet" href="https://substackcdn.com/bundle/theme/main.06a4c4c291d4583811c7.css" />
<style data-pub-theme-postfix></style>
<script async="true" src="https://www.googletagmanager.com/gtag/js?id=G-G8RXW18CW7&l=GA4DataLayer" >
</script>
</head>
<body class="">
<div id="entry">
<div id="main" style="--post-preview-border-radius:var(--border-radius-xs);" class="main typography use-theme-bg"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div data-testid="navbar" class="main-menu"><div class="mainMenuContent-DME8DR"><div style="position:relative;height:93px;" class="pencraft pc-display-flex pc-gap-12 pc-paddingLeft-20 pc-paddingRight-20 pc-paddingTop-0 pc-paddingBottom-0 pc-justifyContent-space-between pc-alignItems-center pc-reset border-bottom-detail-k1F6C4 topBar-pIF0J1"><div style="visibility:visible;flex:1 0 0;" class="logoContainer-p12gJb"><a href="/" native class="pencraft pc-display-contents pc-reset"><div draggable="false" class="pencraft pc-display-flex pc-position-relative pc-reset"><div style="width:40px;height:40px;" class="pencraft pc-display-flex pc-reset bg-white-ZBV5av pc-borderRadius-sm overflow-hidden-WdpwT6 sizing-border-box-DggLA4"><picture class="pencraft pc-display-contents pc-reset"><source type="image/webp" sizes="40px" srcset="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 40w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_80,h_80,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 80w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_120,h_120,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 120w" style="display:none;"/><img style="object-fit:cover;width:40px;height:40px;" src="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png" srcset="https://substackcdn.com/image/fetch/$s_!_Ur2!,w_40,h_40,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 40w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_80,h_80,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 80w, https://substackcdn.com/image/fetch/$s_!_Ur2!,w_120,h_120,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png 120w" sizes="40px" alt="Alex Ewerlöf Notes" draggable="false" class="pencraft pc-reset"/></picture></div></div></a></div><div style="flex-basis:0px;flex-grow:2;min-width:0px;display:flex;justify-content:center;" class="logoTopCenterSlot-hss6WZ"><div style="flex-grow:0;" class="titleContainer-DJYq5v overflowVisible-joA5t0"><h1 id="wordlogo" class="pencraft pc-reset font-pub-headings-FE5byy reset-IxiVJZ title-oOnUGd titleWithWordmark-GfqxEZ"><a href="/" class="pencraft pc-display-contents pc-reset"><img alt="Alex Ewerlöf Notes" src="https://substackcdn.com/image/fetch/$s_!3m6V!,e_trim:10:white/e_trim:10:transparent/h_84,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fbd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png" style="max-height:42px;" class="wordmark-WcDTTu"/></a></h1></div></div><div style="flex-basis:0px;flex-grow:1;min-width:fit-content;" class="pencraft pc-display-flex pc-justifyContent-flex-end pc-alignItems-center pc-reset buttonsContainerContainer-ThaN_w"><div class="buttonsContainer-SJBuep"><div class="pencraft pc-display-flex pc-gap-8 pc-justifyContent-flex-end pc-alignItems-center pc-reset navbar-buttons"><div class="pencraft pc-display-flex pc-gap-4 pc-reset"><span data-state="closed"><button tabindex="0" type="button" aria-label="Search" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_md-gCDS3o priority_tertiary-rlke8z"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-search"><circle cx="11" cy="11" r="8"></circle><path d="m21 21-4.3-4.3"></path></svg></button></span><button tabindex="0" type="button" aria-label="Share Publication" id="radix-P0-4" aria-haspopup="menu" aria-expanded="false" data-state="closed" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_md-gCDS3o priority_tertiary-rlke8z"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-share"><path d="M4 12v8a2 2 0 0 0 2 2h12a2 2 0 0 0 2-2v-8"></path><polyline points="16 6 12 2 8 6"></polyline><line x1="12" x2="12" y1="2" y2="15"></line></svg></button></div><button tabindex="0" type="button" data-testid="noncontributor-cta-button" class="pencraft pc-reset pencraft buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_primary-RfbeYt size_md-gCDS3o">Subscribe</button><button tabindex="0" data-native="true" type="button" data-href="https://substack.com/sign-in?redirect=%2Fp%2Fsli-heterogeneous-vs-homogeneous&amp;for_pub=alexewerlof" class="pencraft pc-reset pencraft buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_tertiary-rlke8z size_md-gCDS3o">Sign in</button></div></div></div></div></div><div style="background-color:#001426;height:94px;"></div></div></div><div><script nonce="ojec8Slr706y9DeQ9hU8iA" type="application/ld+json">{"@context":"https://schema.org","@type":"NewsArticle","url":"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous","mainEntityOfPage":"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous","headline":"Heterogeneous SLI vs Homogeneous SLI","description":"This article defines Heterogeneous and Homogeneous SLIs with examples, illustrations and their pros and cons. It then concludes with a lightweight guide on when to use which one.","image":[{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/$s_!aFXH!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png"}],"datePublished":"2024-09-13T04:37:19+00:00","dateModified":"2024-09-13T04:37:19+00:00","isAccessibleForFree":true,"author":[{"@type":"Person","name":"Alex Ewerl\u00F6f","url":"https://substack.com/@alexewerlof","description":"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who","identifier":"user:87732486","sameAs":["https://twitter.com/alexewerlof"],"image":{"@type":"ImageObject","contentUrl":"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!IRtW!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg"}}],"publisher":{"@type":"Organization","name":"Alex Ewerl\u00F6f Notes","url":"https://blog.alexewerlof.com","description":"Technical Leadership, Reliability Engineering, Growth","interactionStatistic":{"@type":"InteractionCounter","name":"Subscribers","interactionType":"https://schema.org/SubscribeAction","userInteractionCount":10000},"identifier":"pub:1002265","logo":{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","contentUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png"},"image":{"@type":"ImageObject","url":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","contentUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png","thumbnailUrl":"https://substackcdn.com/image/fetch/$s_!_Ur2!,w_128,h_128,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png"},"sameAs":["https://twitter.com/alexewerlof"]},"interactionStatistic":[{"@type":"InteractionCounter","interactionType":"https://schema.org/LikeAction","userInteractionCount":7},{"@type":"InteractionCounter","interactionType":"https://schema.org/ShareAction","userInteractionCount":3},{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":0}]}</script><script nonce="ojec8Slr706y9DeQ9hU8iA" type="application/ld+json">{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Alex Ewerl\u00F6f Notes","item":"https://blog.alexewerlof.com"},{"@type":"ListItem","position":2,"name":"Heterogeneous SLI vs Homogeneous SLI","item":"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous"}]}</script><div aria-label="Post" role="main" class="single-post-container"><div class="container"><div class="single-post"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><article class="typography newsletter-post post"><div role="region" aria-label="Post header" class="post-header"><div class="pencraft pc-display-flex pc-reset post-label"><a href="https://blog.alexewerlof.com/s/sre/?utm_source=substack&amp;utm_medium=menu" class="pencraft pc-reset color-secondary-ls1g8s line-height-20-t4M0El font-meta-MWBumP size-14-MLPa7j weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA">Reliability Engineering</a></div><h1 dir="auto" class="post-title published title-X77sOw">Heterogeneous SLI vs Homogeneous SLI</h1><h3 dir="auto" class="subtitle subtitle-HEEcLo">Cons and pros of each approach and when to use which</h3><div aria-label="Post UFI" role="region" class="pencraft pc-display-flex pc-flexDirection-column pc-paddingBottom-16 pc-reset"><div class="pencraft pc-display-flex pc-paddingTop-16 pc-paddingBottom-16 pc-justifyContent-space-between pc-alignItems-center pc-reset"><div class="pencraft pc-display-flex pc-gap-12 pc-alignItems-center pc-reset byline-wrapper"><div class="pencraft pc-display-flex pc-reset"><div class="pencraft pc-display-flex pc-flexDirection-row pc-gap-8 pc-alignItems-center pc-justifyContent-flex-start pc-reset"><div style="--scale:36px;--offset:9px;--border-width:4.5px;" class="pencraft pc-display-flex pc-flexDirection-row pc-alignItems-center pc-justifyContent-flex-start pc-reset ltr-qDBmby"><a href="https://substack.com/@alexewerlof" aria-label="View Alex Ewerlöf's profile" class="pencraft pc-display-contents pc-reset"><div style="--scale:36px;" tabindex="0" class="pencraft pc-display-flex pc-width-36 pc-height-36 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA animate-XFJxE4 outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 pressable-sm-YIJFKJ showFocus-sk_vEm container-TAtrWj interactive-UkK0V6 avatar-u8q6xB last-JfNEJ_"><div style="--scale:36px;" title="Alex Ewerlöf" class="pencraft pc-display-flex pc-width-36 pc-height-36 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_72,h_72,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_108,h_108,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x"/><img src="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg" alt="Alex Ewerlöf's avatar" srcset="https://substackcdn.com/image/fetch/$s_!IRtW!,w_36,h_36,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 1x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_72,h_72,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 2x, https://substackcdn.com/image/fetch/$s_!IRtW!,w_108,h_108,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg 3x" width="36" height="36" draggable="false" class="img-OACg1c object-fit-cover-u4ReeV pencraft pc-reset"/></picture></div></div></a></div></div></div><div class="pencraft pc-display-flex pc-flexDirection-column pc-reset"><div class="pencraft pc-reset color-primary-zABazT line-height-20-t4M0El font-meta-MWBumP size-11-NuY2Zx weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA"><span style="min-width:0;" data-state="closed"><a href="https://substack.com/@alexewerlof" class="pencraft pc-reset decoration-hover-underline-ClDVRM reset-IxiVJZ">Alex Ewerlöf</a></span></div><div class="pencraft pc-display-flex pc-gap-4 pc-reset"><div class="pencraft pc-reset color-secondary-ls1g8s line-height-20-t4M0El font-meta-MWBumP size-11-NuY2Zx weight-medium-fw81nC transform-uppercase-yKDgcq reset-IxiVJZ meta-EgzBVA"><time datetime="2024-09-13T04:37:19.200Z" title="2024-09-13T04:37:19.200Z">Sep 13, 2024</time></div></div></div></div></div><div class="pencraft pc-display-flex pc-gap-16 pc-justifyContent-space-between pc-alignItems-center pc-reset flex-grow-rzmknG post-ufi"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><div class="like-button-container post-ufi-button style-button"><button tabindex="0" type="button" aria-label="Like (7)" aria-pressed="false" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-heart"><path d="M19 14c1.49-1.46 3-3.21 3-5.5A5.5 5.5 0 0 0 16.5 3c-1.76 0-3 .5-4.5 2-1.5-1.5-2.74-2-4.5-2A5.5 5.5 0 0 0 2 8.5c0 2.3 1.5 4.05 3 5.5l7 7Z"></path></svg></g></svg><div class="label">7</div></button></div><button tabindex="0" type="button" aria-label="View comments (0)" data-href="https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous/comments" class="pencraft pc-reset pencraft post-ufi-button style-button post-ufi-comment-button no-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-message-circle"><path d="M7.9 20A9 9 0 1 0 4 16.1L2 22Z"></path></svg></g></svg></button><button tabindex="0" type="button" id="radix-P0-27" aria-haspopup="menu" aria-expanded="false" data-state="closed" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="2" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg" class="icon"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg><div class="label">3</div></button></div><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><div class="label">Share</div></button></div></div></div></div><div class="visibility-check"></div><div><div class="dt-post-body"><div class="available-content"><div dir="auto" class="body markup"><p><span>At the heart of the </span><a href="https://blog.alexewerlof.com/p/sli">Service Levels</a><span> is the ratio between </span><a href="https://blog.alexewerlof.com/p/sli-good">good</a><span> and </span><a href="https://blog.alexewerlof.com/p/valid-vs-total">valid</a><span>:</span></p><ul><li><p><span>Percentage of </span><code>requests</code><span> where </span><code>response.latency &lt; 300ms</code></p></li><li><p><span>Percentage of </span><code>uptime probes</code><span> where </span><code>response.code == 200</code></p></li><li><p><span>Percentage of </span><code>database records</code><span> where </span><code>fields.*.age &lt; 365 days</code></p></li><li><p><span>Percentage of </span><code>authenticated API requests</code><span> where </span><code>http_response.code &lt; 500</code></p></li></ul><p>When it comes to implement and calculate those percentages, there are two approaches:</p><ul><li><p><strong>Heterogeneous:</strong><span> good and valid are two different metrics with an assumed correlation.</span></p></li><li><p><strong>Homogeneous:</strong><span> good and valid come from processing the same metric where good and valid are tightly coupled</span></p></li></ul><p>This article introduces both types with examples and illustrations ending with a recommendation.</p><h2 class="header-anchor-post">Heterogeneous<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§heterogeneous" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/heterogeneous" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h2><p>This type of SLI queries two different metrics to count the number of:</p><p>Good and valid:</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLI = \frac{\text{good}}{\text{valid}} \times 100\)</span></div></div><p>or good and bad:</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLI = \frac{\text{good}}{\text{good} + \text{bad}} \times 100
\)</span></div></div><p>or bad and valid:</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLI = \frac{\text{valid} - \text{bad}}{\text{valid}} \times 100
\)</span></div></div><p>Regardless of the approach, it ends up querying two metrics.</p><p>Example: Availability of online purchase flow:</p><ul><li><p>Valid: number of unique sessions where the user clicked on the “Pay” button on the check out page</p></li><li><p>Bad: number of payments failing due to payment gateway issues</p></li><li><p>Good = Valid - Bad</p></li></ul><p><em><span>Note: we deliberately filter out other failures like: when the user doesn’t have enough money, or entered the wrong payment information because </span><a href="https://blog.alexewerlof.com/p/responsible-for-control">you should never be responsible for what you don't control</a><span>.</span></em></p><p>On the surface, it looks reasonable, but in practice there are multiple nuances. The biggest issue is the assumed correlation between the datapoints of two different metrics over time:</p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!aFXH!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!aFXH!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 424w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 848w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1272w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png" width="1017" height="720" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:720,&quot;width&quot;:1017,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:53530,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!aFXH!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 424w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 848w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1272w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a><figcaption class="image-caption">In this lookback window, there are 6 good events and 8 valid events but they are not corelated</figcaption></figure></div><p>This is because the data points of two separate metrics don’t exactly match. As a result, for any type of lookback window (e.g. SLS or Alerting), we may end up with an inaccurate measurement.</p><p>The problem doesn’t stop at the timestamp level. It is practically impossible to guarantee a 1-1 mapping between valid events and good events when they’re measuring different things, at different locations, and different times.</p><p><span>Another obvious issue is the fact that we need to measure, store, and query two separate metrics (</span><code>valid</code><span> and either </span><code>good</code><span> or </span><code>bad</code><span>).</span></p><h3 class="header-anchor-post">Pros<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§pros" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/pros" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h3><ul><li><p>Can correlate events across different systems which may map better to how the consumers perceives reliability of the service</p></li><li><p>Easier to reason about for beginners</p></li><li><p>Easier to implement by conventional Observability providers (in the next articles we’ll review how Elastic, Datadog, and Grafana implement service levels)</p></li></ul><div data-component-name="SubscribeWidget" class="subscribe-widget"><div class="pencraft pc-display-flex pc-justifyContent-center pc-reset"><div class="container-IpPqBD"><form action="/api/v1/free?nojs=true" method="post" novalidate class="form form-M5sC90"><input type="hidden" name="first_url" value/><input type="hidden" name="first_referrer" value/><input type="hidden" name="current_url"/><input type="hidden" name="current_referrer"/><input type="hidden" name="first_session_url" value/><input type="hidden" name="first_session_referrer" value/><input type="hidden" name="referral_code"/><input type="hidden" name="source" value="subscribe-widget"/><input type="hidden" name="referring_pub_id"/><input type="hidden" name="additional_referring_pub_ids"/><input type="hidden" name="source_post_id" value="148798453"/><div class="sideBySideWrap-vGXrwP"><div class="emailInputWrapper-QlA86j"><div class="pencraft pc-display-flex pc-minWidth-0 pc-position-relative pc-reset flex-auto-j3S2WA"><input name="email" placeholder="Type your email..." type="email" class="pencraft emailInput-OkIMeB input-y4v6N4 inputText-pV_yWb"/></div></div><button tabindex="0" type="submit" disabled class="pencraft pc-reset pencraft rightButton primary subscribe-btn button-VFSdkv buttonBase-GK1x3M"><span class="button-text ">Subscribe</span></button></div><div id="error-container"></div></form></div></div></div><h3 class="header-anchor-post">Cons<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§cons" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/cons" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h3><ul><li><p>It might be harder to work with two datasets due to broken correlation between datapoints.</p></li><li><p>Less efficient due to requiring 2 metrics</p></li></ul><h2 class="header-anchor-post">Homogeneous<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§homogeneous" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/homogeneous" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h2><p>Homogeneous SLIs come directly from the fact that the SLI formula is a percentage:</p><div data-component-name="Latex" class="pencraft pc-display-flex pc-paddingTop-4px pc-paddingBottom-4px pc-justifyContent-center pc-reset flex-grow-rzmknG latex-rendered"><div class="pencraft pc-display-flex pc-flexDirection-column pc-justifyContent-center pc-reset"><span style="display:block;">\(SLI = \frac{\text{good}}{\text{valid}} \times 100\)</span></div></div><p>All you have to do is to:</p><ol><li><p>Filter the metric to only contain valid data points</p></li><li><p>Go through the data points and count the number of good (or bad) events</p></li><li><p>Divide it by the total number of data points</p></li></ol><p>It’s easier to show it with a diagram:</p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!6B2-!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!6B2-!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 424w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 848w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1272w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png" width="1015" height="676" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/db6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:676,&quot;width&quot;:1015,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:52288,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!6B2-!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 424w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 848w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1272w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a><figcaption class="image-caption">In this lookback window, 6 out of 8 events are good</figcaption></figure></div><p>The biggest advantage of this method is the reliable correlation between good, bad and valid.</p><p><em><span>Note: an upcoming feature of </span><a href="https://slc.alexewerlof.com/">SLC</a><span>, introduces a simulator. It uses an O(1) algorithm to process the metric data in one pass. I’ll write more about that technique once the feature is out.</span></em></p><div class="subscription-widget-wrap"><div class="subscription-widget show-subscribe"><div class="preamble"><p>If you want to stay in the know for SLC development and learn more along the way, you can subscribe for free.</p></div><div data-component-name="SubscribeWidget" class="subscribe-widget"><div class="pencraft pc-display-flex pc-justifyContent-center pc-reset"><div class="container-IpPqBD"><form action="/api/v1/free?nojs=true" method="post" novalidate class="form form-M5sC90"><input type="hidden" name="first_url" value/><input type="hidden" name="first_referrer" value/><input type="hidden" name="current_url"/><input type="hidden" name="current_referrer"/><input type="hidden" name="first_session_url" value/><input type="hidden" name="first_session_referrer" value/><input type="hidden" name="referral_code"/><input type="hidden" name="source" value="subscribe-widget-preamble"/><input type="hidden" name="referring_pub_id"/><input type="hidden" name="additional_referring_pub_ids"/><input type="hidden" name="source_post_id" value="148798453"/><div class="sideBySideWrap-vGXrwP"><div class="emailInputWrapper-QlA86j"><div class="pencraft pc-display-flex pc-minWidth-0 pc-position-relative pc-reset flex-auto-j3S2WA"><input name="email" placeholder="Type your email..." type="email" class="pencraft emailInput-OkIMeB input-y4v6N4 inputText-pV_yWb"/></div></div><button tabindex="0" type="submit" disabled class="pencraft pc-reset pencraft rightButton primary subscribe-btn button-VFSdkv buttonBase-GK1x3M"><span class="button-text ">Subscribe</span></button></div><div id="error-container"></div></form></div></div></div></div></div><p>An obvious advantage of a homogeneous SLI is that it only needs to measure, store, and query one metric.</p><p>The downside is that your SLI may not readily be one metric. You may need to use a data processing pipeline that takes in 2 metrics in and spits out a clean homogeneous SLI. This can introduce a delay and cost to your setup.</p><div class="captioned-image-container"><figure><a target="_blank" href="https://substackcdn.com/image/fetch/$s_!CzlQ!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png" data-component-name="Image2ToDOM" class="image-link image2 is-viewable-img can-restack"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!CzlQ!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 424w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 848w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1272w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1456w" sizes="100vw"/><img src="https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png" width="1028" height="367" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:367,&quot;width&quot;:1028,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:37047,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" alt srcset="https://substackcdn.com/image/fetch/$s_!CzlQ!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 424w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 848w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1272w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1456w" sizes="100vw" loading="lazy" class="sizing-normal"/></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>The good news is that most metrics don’t need this type of processing. For example:</p><ul><li><p><code>Uptime calculation:</code><span> divide the percentage of successful probes during the window, multiply by 100</span></p></li><li><p><code>Percentage of authenticated requests where latency &lt; 200ms</code><span>: find all the authenticated requests in the window, filter out any events where latency ≥ 200 and divide this count to the total number of requests x 100</span></p></li></ul><h3 class="header-anchor-post">Pros<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§pros" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/pros" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h3><ul><li><p>It is more intuitive because it’s closer to how normalized SLI is literally defined</p></li><li><p><span>It requires half as many metrics (only </span><code>valid</code><span>)</span></p></li><li><p>The SLS calculations essentially turns into a percentile calculation so it is easier to reason about the dataset</p></li></ul><h3 class="header-anchor-post">Cons<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§cons" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/cons" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h3><ul><li><p>When the good and valid come from different systems, it requires extra processing to corelate the events which adds to the cost and complexity</p></li><li><p>None of the observability providers that I have investigated (Datadog, Elastic, Grafana) support homogeneous metrics out of the box.</p></li></ul><h1 class="header-anchor-post">When to use which?<div class="pencraft pc-display-flex pc-alignItems-center pc-position-absolute pc-reset header-anchor-parent"><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div id="§when-to-use-which" class="pencraft pc-reset header-anchor offset-top"></div><button tabindex="0" type="button" aria-label="Link" data-href="https://blog.alexewerlof.com/i/148798453/when-to-use-which" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_sm-G3LciD priority_secondary-S63h9o"><svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-link"><path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path><path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path></svg></button></div></div></h1><p>Whether you use homogeneous or heterogeneous metrics depends on how the consumers perceive reliability, your tooling, and budget (time, and money).</p><p>Homogeneous metrics are easier to reason about and often come naturally out of the box.</p><p>If you can ensure a tight coupling between the two metrics, a heterogenous metric can work too.</p><div><hr/></div><p><em>These posts take anywhere from a few hours to a few days to ideate, draft, research, illustrate, edit, and publish. I pull these hours from my private time, vacation days and weekends.</em></p><p><em>Recently I went down in working hours and salary by 10% to be able to spend more time learning and sharing my experience with the public.</em></p><p><em><a href="https://blog.alexewerlof.com/p/faq#%C2%A7payment">My monetization strategy</a><span> is to give away most content for free because I believe information should be free and accessible. You can support this cause by sparing a few bucks for a paid subscription. As a token of appreciation, you get access to the Pro-Tips sections (on some articles) as well as my online book </span><a href="https://blog.alexewerlof.com/p/rem">Reliability Engineering Mindset</a><span>. Right now, you can get 20% off via </span><a href="https://blog.alexewerlof.com/protipsdiscount">this link</a><span>. You can also </span><a href="https://blog.alexewerlof.com/leaderboard">invite your friends</a><span> to gain free access or get a discounted group subscription. There’s also a </span><a href="https://blog.alexewerlof.com/leaderboard">referral bonus program to gain free subscriptions</a><span>.</span></em></p><p><em>Thanks in advance for helping these words reach further and impact the software engineering community.</em></p><div data-attrs="{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share&quot;,&quot;text&quot;:&quot;Share&quot;}" data-component-name="CaptionedButtonToDOM" class="captioned-button-wrap"><div class="preamble"><p class="cta-caption">If you find this post insightful, please share it in your circles to inspire others.</p></div><p data-attrs="{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share&quot;,&quot;text&quot;:&quot;Share&quot;}" data-component-name="ButtonCreateButton" class="button-wrapper"><a href="https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&amp;utm_medium=email&amp;utm_content=share&amp;action=share" class="button primary"><span>Share</span></a></p></div></div></div><div class="visibility-check"></div></div><div class="post-footer"><div class="pencraft pc-display-flex pc-gap-16 pc-paddingTop-16 pc-paddingBottom-16 pc-justifyContent-space-between pc-alignItems-center pc-reset flex-grow-rzmknG border-top-detail-themed-k9TZAY border-bottom-detail-themed-Ua9186 post-ufi"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><div class="like-button-container post-ufi-button style-button"><button tabindex="0" type="button" aria-label="Like (7)" aria-pressed="false" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-heart"><path d="M19 14c1.49-1.46 3-3.21 3-5.5A5.5 5.5 0 0 0 16.5 3c-1.76 0-3 .5-4.5 2-1.5-1.5-2.74-2-4.5-2A5.5 5.5 0 0 0 2 8.5c0 2.3 1.5 4.05 3 5.5l7 7Z"></path></svg></g></svg><div class="label">7</div></button></div><button tabindex="0" type="button" aria-label="View comments (0)" data-href="https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous/comments" class="pencraft pc-reset pencraft post-ufi-button style-button post-ufi-comment-button no-label with-border"><svg aria-hidden="true" style="height:20px;width:20px;" width="20" height="20" viewBox="0 0 24 24" fill="#000000" stroke-width="2" stroke="#000" xmlns="http://www.w3.org/2000/svg" class="icon"><g><svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-message-circle"><path d="M7.9 20A9 9 0 1 0 4 16.1L2 22Z"></path></svg></g></svg></button><button tabindex="0" type="button" id="radix-P0-56" aria-haspopup="menu" aria-expanded="false" data-state="closed" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><svg aria-hidden="true" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="2" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg" class="icon"><g><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg><div class="label">3</div></button></div><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft post-ufi-button style-button has-label with-border"><div class="label">Share</div></button></div></div></div></div></article></div></div></div><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div class="visibility-check"></div><div id="discussion" class="pencraft pc-display-flex pc-flexDirection-column pc-gap-16 pc-paddingTop-32 pc-paddingBottom-32 pc-reset"><div class="pencraft pc-display-flex pc-flexDirection-column pc-gap-32 pc-reset container"><h4 class="pencraft pc-reset line-height-24-jnGwiv font-display-nhmvtD size-20-P_cSRT weight-bold-DmI9lw reset-IxiVJZ">Discussion about this post</h4><div class="pencraft pc-alignSelf-flex-start pc-reset"><div class="pencraft pc-display-flex pc-flexDirection-column pc-position-relative pc-minWidth-0 pc-reset bg-primary-zk6FDl outline-detail-vcQLyr pc-borderRadius-sm overflow-hidden-WdpwT6"><div dir="ltr" data-orientation="horizontal" class="pencraft pc-display-flex pc-flexDirection-column pc-reset flex-grow-rzmknG"><div style="outline:none;" tabindex="-1" aria-label="Select discussion type" role="tablist" aria-orientation="horizontal" data-orientation="horizontal" class="pencraft pc-display-flex pc-gap-4 pc-padding-4 pc-position-relative pc-reset cursor-default-flE2S1 pc-borderRadius-sm overflow-auto-7WTsTi scrollBar-hidden-HcAIpI"><button tabindex="-1" type="button" role="tab" aria-selected="true" aria-controls="radix-P0-70-content-comments" data-state="active" id="radix-P0-70-trigger-comments" data-orientation="horizontal" data-radix-collection-item class="pencraft pc-reset flex-auto-j3S2WA pencraft segment-j4TeZ4 buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_quaternary-kpMibu size_sm-G3LciD">Comments</button><button tabindex="-1" type="button" role="tab" aria-selected="false" aria-controls="radix-P0-70-content-restacks" data-state="inactive" id="radix-P0-70-trigger-restacks" data-orientation="horizontal" data-radix-collection-item class="pencraft pc-reset flex-auto-j3S2WA pencraft segment-j4TeZ4 buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_quaternary-kpMibu size_sm-G3LciD">Restacks</button><div class="pencraft pc-position-absolute pc-height-32 pc-reset bg-secondary-UUD3_J pc-borderRadius-xs sizing-border-box-DggLA4 highlight-U002IP"></div></div></div><div class="pencraft pc-display-flex pc-alignItems-center pc-reset arrowButtonContainer-O4uSiH arrowButtonOverlaidContainer-t10AyH left-Tg8vqp"><div class="overlay-zrMCxn primary-lv_sOW"></div></div><div class="pencraft pc-display-flex pc-alignItems-center pc-reset arrowButtonContainer-O4uSiH arrowButtonOverlaidContainer-t10AyH right-i3oWGi"><div class="overlay-zrMCxn primary-lv_sOW"></div></div></div></div></div><div id="substack-comments" class="single-post-section comments-section"><div class="container"><div class="visibility-check"></div><div data-test-id="comment-input" class="pencraft pc-display-flex pc-reset flex-grow-rzmknG"><form class="comment-input-form form-CkZ7Kt"><div style="--scale:32px;" class="pencraft pc-display-flex pc-width-32 pc-height-32 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj"><div style="--scale:32px;" title="User" class="pencraft pc-display-flex pc-width-32 pc-height-32 pc-justifyContent-center pc-alignItems-center pc-position-relative pc-reset bg-secondary-UUD3_J flex-auto-j3S2WA outline-detail-vcQLyr pc-borderRadius-full overflow-hidden-WdpwT6 sizing-border-box-DggLA4 container-TAtrWj"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!TnFC!,w_32,h_32,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 1x, https://substackcdn.com/image/fetch/$s_!TnFC!,w_64,h_64,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 2x, https://substackcdn.com/image/fetch/$s_!TnFC!,w_96,h_96,c_fill,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 3x"/><img src="https://substackcdn.com/image/fetch/$s_!TnFC!,w_32,h_32,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png" alt="User's avatar" srcset="https://substackcdn.com/image/fetch/$s_!TnFC!,w_32,h_32,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 1x, https://substackcdn.com/image/fetch/$s_!TnFC!,w_64,h_64,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 2x, https://substackcdn.com/image/fetch/$s_!TnFC!,w_96,h_96,c_fill,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack.com%2Fimg%2Favatars%2Fdefault-light.png 3x" width="32" height="32" draggable="false" class="img-OACg1c object-fit-cover-u4ReeV pencraft pc-reset"/></picture></div></div><div class="pencraft pc-display-flex pc-flexDirection-column pc-gap-8 pc-reset flex-grow-rzmknG"><div class="pencraft pc-display-flex pc-flexDirection-column pc-boxShadow-xs pc-reset bg-primary-zk6FDl flex-grow-rzmknG border-detail-EGrm7T pc-borderRadius-sm"><textarea name="body" placeholder="Write a comment..." aria-label="Write a comment..." rows="4" class="pencraft input-qHk4bN autogrowing-_ipn9Y textarea-GbEjRX inputText-pV_yWb unstyled-IJLUJU"></textarea></div><div data-state="closed" class="pencraft pc-display-flex pc-flexDirection-column pc-reset overflow-hidden-WdpwT6"></div></div></form></div></div></div></div><div class="single-post-section"><div class="container"><div class="visibility-check"></div><div style="margin-left:-8px;margin-right:-8px;" aria-label="Top Posts Footer" role="region" class="pencraft pc-paddingTop-24 pc-paddingBottom-24 pc-reset"><div class="portable-archive empty-list"><div aria-label="Archive sort tabs" role="navigation" class="pencraft pc-display-flex pc-gap-12 pc-paddingLeft-8 pc-paddingRight-8 pc-paddingBottom-16 pc-justifyContent-space-between pc-alignItems-center pc-reset"><div class="pencraft pc-display-flex pc-flexDirection-column pc-position-relative pc-minWidth-0 pc-reset bg-primary-zk6FDl outline-detail-vcQLyr pc-borderRadius-sm overflow-hidden-WdpwT6"><div dir="ltr" data-orientation="horizontal" class="pencraft pc-display-flex pc-flexDirection-column pc-reset flex-grow-rzmknG"><div style="outline:none;" tabindex="-1" aria-label="Tabs" role="tablist" aria-orientation="horizontal" data-orientation="horizontal" class="pencraft pc-display-flex pc-gap-4 pc-padding-4 pc-position-relative pc-reset cursor-default-flE2S1 pc-borderRadius-sm overflow-auto-7WTsTi scrollBar-hidden-HcAIpI"><button tabindex="-1" type="button" role="tab" aria-selected="true" aria-controls="radix-P0-83-content-top" data-state="active" id="radix-P0-83-trigger-top" data-orientation="horizontal" data-radix-collection-item class="pencraft pc-reset flex-auto-j3S2WA pencraft segment-j4TeZ4 buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_quaternary-kpMibu size_sm-G3LciD">Top</button><button tabindex="-1" type="button" role="tab" aria-selected="false" aria-controls="radix-P0-83-content-new" data-state="inactive" id="radix-P0-83-trigger-new" data-orientation="horizontal" data-radix-collection-item class="pencraft pc-reset flex-auto-j3S2WA pencraft segment-j4TeZ4 buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_quaternary-kpMibu size_sm-G3LciD">Latest</button><button tabindex="-1" type="button" role="tab" aria-selected="false" aria-controls="radix-P0-83-content-community" data-state="inactive" id="radix-P0-83-trigger-community" data-orientation="horizontal" data-radix-collection-item class="pencraft pc-reset flex-auto-j3S2WA pencraft segment-j4TeZ4 buttonBase-GK1x3M buttonText-X0uSmG buttonStyle-r7yGCK priority_quaternary-kpMibu size_sm-G3LciD">Discussions</button><div class="pencraft pc-position-absolute pc-height-32 pc-reset bg-secondary-UUD3_J pc-borderRadius-xs sizing-border-box-DggLA4 highlight-U002IP"></div></div></div><div class="pencraft pc-display-flex pc-alignItems-center pc-reset arrowButtonContainer-O4uSiH arrowButtonOverlaidContainer-t10AyH left-Tg8vqp"><div class="overlay-zrMCxn primary-lv_sOW"></div></div><div class="pencraft pc-display-flex pc-alignItems-center pc-reset arrowButtonContainer-O4uSiH arrowButtonOverlaidContainer-t10AyH right-i3oWGi"><div class="overlay-zrMCxn primary-lv_sOW"></div></div></div><button tabindex="0" type="button" aria-label="Search" class="pencraft pc-reset pencraft iconButton-mq_Et5 iconButtonBase-dJGHgN buttonBase-GK1x3M buttonStyle-r7yGCK size_md-gCDS3o priority_tertiary-rlke8z"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-search"><circle cx="11" cy="11" r="8"></circle><path d="m21 21-4.3-4.3"></path></svg></button></div><div class="portable-archive-list"><p class="portable-archive-empty dt-archive-empty-state">No posts</p></div></div></div></div></div><div class="visibility-check"></div><div class="pencraft pc-display-contents pc-reset pubInvertedTheme-U483dz"><div class="pencraft pc-display-flex pc-flexDirection-column pc-alignItems-center pc-justifyContent-center pc-padding-48 pc-mobile-padding-24 pc-reset bg-primary-zk6FDl container-jsOc9L"><div class="pencraft pc-display-flex pc-flexDirection-column pc-alignItems-center pc-gap-24 pc-flexWrap-wrap pc-reset content-jLbYeh"><h3 class="pencraft pc-reset color-primary-zABazT align-center-y7ZD4w line-height-28-s562kJ font-display-nhmvtD size-24-lFU3ly weight-semibold-uqA4FV reset-IxiVJZ">Ready for more?</h3><div class="container-IpPqBD"><form action="/api/v1/free?nojs=true" method="post" novalidate class="form form-M5sC90"><input type="hidden" name="first_url" value/><input type="hidden" name="first_referrer" value/><input type="hidden" name="current_url"/><input type="hidden" name="current_referrer"/><input type="hidden" name="first_session_url" value/><input type="hidden" name="first_session_referrer" value/><input type="hidden" name="referral_code"/><input type="hidden" name="source" value="subscribe_footer"/><input type="hidden" name="referring_pub_id"/><input type="hidden" name="additional_referring_pub_ids"/><div class="sideBySideWrap-vGXrwP"><div class="emailInputWrapper-QlA86j"><div class="pencraft pc-display-flex pc-minWidth-0 pc-position-relative pc-reset flex-auto-j3S2WA"><input name="email" placeholder="Type your email..." type="email" class="pencraft emailInput-OkIMeB emailInputOnAccentBackground-TfaCGr input-y4v6N4 inputText-pV_yWb"/></div></div><button tabindex="0" type="submit" disabled class="pencraft pc-reset pencraft rightButton primary subscribe-btn button-VFSdkv buttonOnAccentBackground-vmEt94 buttonBase-GK1x3M"><span class="button-text ">Subscribe</span></button></div><div id="error-container"></div></form></div></div></div></div></div></div></div><div class="pencraft pc-display-flex pc-flexDirection-column pc-reset container-K5XPov"></div><div class="pencraft pc-display-contents pc-reset pubTheme-yiXxQA"><div class="footer-wrap compact-footer"><div class="visibility-check"></div><div class="footer custom-themed-background"><div class="pencraft pc-display-flex pc-gap-12 pc-alignItems-center pc-reset flex-grow-rzmknG"><div class="pencraft pc-display-flex pc-minWidth-0 pc-reset flex-grow-rzmknG nowrap-QngyoB"><span><span>© 2026 Alex Ewerlöf</span><span> · </span><a href="https://substack.com/privacy" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Privacy</a><span> ∙ </span><a href="https://substack.com/tos" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Terms</a><span> ∙ </span><a href="https://substack.com/ccpa#personal-data-collected" target="_blank" rel="noopener" class="pencraft pc-reset decoration-underline-ClTkYc">Collection notice</a></span></div><div class="pencraft pc-display-flex pc-reset"><div class="pencraft pc-display-flex pc-gap-8 pc-justifyContent-center pc-alignItems-center pc-reset footerButtons-ap9Sk7"><a data-native="true" href="https://substack.com/signup?utm_source=substack&amp;utm_medium=web&amp;utm_content=footer" class="footerSubstackCta-v5HWfj sizeSm-F_aC8H"><svg aria-hidden="true" width="1000" height="1000" viewBox="0 0 1000 1000" fill="#ff6719" stroke-width="1.8" stroke="none" xmlns="http://www.w3.org/2000/svg"><g><path d="M764.166 348.371H236.319V419.402H764.166V348.371Z"></path><path d="M236.319 483.752V813.999L500.231 666.512L764.19 813.999V483.752H236.319Z"></path><path d="M764.166 213H236.319V284.019H764.166V213Z"></path></g></svg> Start your Substack</a><a data-native="true" href="https://substack.com/app/app-store-redirect?utm_campaign=app-marketing&amp;utm_content=web-footer-button" class="footerSubstackCta-v5HWfj getTheApp-Yk3w1O noIcon-z7v9D8 sizeSm-F_aC8H sizeSmNoIcon-KRHkpZ">Get the app</a></div></div><div class="pencraft pc-display-flex pc-minWidth-0 pc-justifyContent-flex-end pc-reset flex-grow-rzmknG"><div translated class="pencraft pc-reset reset-IxiVJZ footer-slogan-blurb"><a href="https://substack.com" data-native="true">Substack</a> is the home for great culture</div></div></div></div></div></div></div><div role="region" aria-label="Notifications (F8)" tabindex="-1" style="pointer-events:none;"><ol tabindex="-1" style="--offset:0px;z-index:1000;" class="viewport-_BM4Bg"></ol></div><div></div><script suppressHydrationWarning nonce="ojec8Slr706y9DeQ9hU8iA">window.__staticRouterHydrationData = JSON.parse("{\"loaderData\":{},\"actionData\":null,\"errors\":null}");</script>
</div>
<script src="https://js.sentry-cdn.com/6c2ff3e3828e4017b7faf7b63e24cdf8.min.js" crossorigin="anonymous"></script>
<script nonce="ojec8Slr706y9DeQ9hU8iA">
window.Sentry && window.Sentry.onLoad(function() {
window.Sentry.init({
environment: window._preloads.sentry_environment,
dsn: window._preloads.sentry_dsn,
})
})
</script>
<script nonce="ojec8Slr706y9DeQ9hU8iA">window._preloads = JSON.parse("{\"cspNonce\":\"ojec8Slr706y9DeQ9hU8iA\",\"isEU\":false,\"language\":\"en\",\"country\":\"US\",\"leaderboardCountries\":[\"ES\",\"FR\",\"GB\",\"IT\",\"NL\"],\"enabledLeaderboardCountries\":[\"ES\",\"FR\",\"GB\",\"IT\",\"NL\"],\"userLocale\":{\"language\":\"en\",\"region\":\"US\",\"source\":\"accept-language\"},\"base_url\":\"https://blog.alexewerlof.com\",\"stripe_publishable_key\":\"pk_live_51QfnARLDSWi1i85FBpvw6YxfQHljOpWXw8IKi5qFWEzvW8HvoD8cqTulR9UWguYbYweLvA16P7LN6WZsGdZKrNkE00uGbFaOE3\",\"captcha_site_key\":\"6LeI15YsAAAAAPXyDcvuVqipba_jEFQCjz1PFQoz\",\"pub\":{\"apple_pay_disabled\":false,\"apex_domain\":null,\"author_id\":87732486,\"byline_images_enabled\":true,\"bylines_enabled\":true,\"chartable_token\":null,\"community_enabled\":true,\"copyright\":\"Alex Ewerl\u00F6f\",\"cover_photo_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/ffddf167-cd34-41aa-9334-ad26acca3ed2_600x600.png\",\"created_at\":\"2022-07-14T22:27:58.683Z\",\"custom_domain_optional\":false,\"custom_domain\":\"blog.alexewerlof.com\",\"default_comment_sort\":\"oldest_first\",\"default_coupon\":null,\"default_group_coupon\":\"d8f4bfde\",\"default_show_guest_bios\":true,\"email_banner_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/74f8e318-c490-4be2-b868-df0285fc2f3e_1100x220.png\",\"email_from_name\":\"Alex Ewerl\u00F6f Notes\",\"email_from\":null,\"embed_tracking_disabled\":false,\"explicit\":false,\"expose_paywall_content_to_search_engines\":true,\"fb_pixel_id\":null,\"fb_site_verification_token\":null,\"flagged_as_spam\":false,\"founding_subscription_benefits\":[\"1:1 chat, 60m video call\"],\"free_subscription_benefits\":[\"All the public posts\"],\"ga_pixel_id\":null,\"google_site_verification_token\":\"HIy4u2xUDZkIs6P0KJw9TSYeq7KqXSPAQvZIs9911qU\",\"google_tag_manager_token\":\"\",\"hero_image\":null,\"hero_text\":\"Technical Leadership, Reliability Engineering, Growth\",\"hide_intro_subtitle\":null,\"hide_intro_title\":null,\"hide_podcast_feed_link\":false,\"homepage_type\":\"newspaper\",\"id\":1002265,\"image_thumbnails_always_enabled\":false,\"invite_only\":false,\"hide_podcast_from_pub_listings\":false,\"hide_podcast_from_pub_listings_prior_to\":null,\"language\":\"en\",\"logo_url_wide\":\"https://substackcdn.com/image/fetch/$s_!3m6V!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fbd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png\",\"logo_url\":\"https://substackcdn.com/image/fetch/$s_!_Ur2!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png\",\"minimum_group_size\":2,\"moderation_enabled\":true,\"name\":\"Alex Ewerl\u00F6f Notes\",\"paid_subscription_benefits\":[\"The pro-tips on all articles\",\"Support spending my private time to write\",\"Access to full archive\"],\"parsely_pixel_id\":null,\"chartbeat_domain\":null,\"payments_state\":\"enabled\",\"paywall_free_trial_enabled\":true,\"podcast_art_url\":null,\"paid_podcast_episode_art_url\":null,\"podcast_byline\":null,\"podcast_description\":null,\"podcast_enabled\":false,\"podcast_feed_url\":null,\"podcast_title\":null,\"post_preview_limit\":null,\"primary_user_id\":87732486,\"require_clickthrough\":false,\"show_pub_podcast_tab\":false,\"show_recs_on_homepage\":true,\"subdomain\":\"alexewerlof\",\"subscriber_invites\":0,\"support_email\":null,\"theme_var_background_pop\":\"#786CFF\",\"theme_var_color_links\":false,\"theme_var_cover_bg_color\":null,\"trial_end_override\":null,\"twitter_pixel_id\":null,\"type\":\"newsletter\",\"post_reaction_faces_enabled\":true,\"is_personal_mode\":false,\"plans\":[{\"id\":\"monthly7_5eur\",\"object\":\"plan\",\"active\":true,\"aggregate_usage\":null,\"amount\":750,\"amount_decimal\":\"750\",\"billing_scheme\":\"per_unit\",\"created\":1728579524,\"currency\":\"eur\",\"interval\":\"month\",\"interval_count\":1,\"livemode\":true,\"metadata\":{\"substack\":\"yes\"},\"meter\":null,\"nickname\":\"\u20AC7.50 a month\",\"product\":\"prod_R0QYoetykRH93k\",\"tiers_mode\":null,\"transform_usage\":null,\"trial_period_days\":null,\"usage_type\":\"licensed\",\"currency_options\":{\"aud\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1300,\"unit_amount_decimal\":\"1300\"},\"brl\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":4400,\"unit_amount_decimal\":\"4400\"},\"cad\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1300,\"unit_amount_decimal\":\"1300\"},\"chf\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":800,\"unit_amount_decimal\":\"800\"},\"dkk\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":6000,\"unit_amount_decimal\":\"6000\"},\"eur\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":750,\"unit_amount_decimal\":\"750\"},\"gbp\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":700,\"unit_amount_decimal\":\"700\"},\"inr\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":82500,\"unit_amount_decimal\":\"82500\"},\"jpy\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1500,\"unit_amount_decimal\":\"1500\"},\"mxn\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":15000,\"unit_amount_decimal\":\"15000\"},\"nok\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"},\"nzd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":1500,\"unit_amount_decimal\":\"1500\"},\"pln\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":3300,\"unit_amount_decimal\":\"3300\"},\"sek\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"},\"usd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":900,\"unit_amount_decimal\":\"900\"}}},{\"id\":\"yearly74eur\",\"object\":\"plan\",\"active\":true,\"aggregate_usage\":null,\"amount\":7400,\"amount_decimal\":\"7400\",\"billing_scheme\":\"per_unit\",\"created\":1728579524,\"currency\":\"eur\",\"interval\":\"year\",\"interval_count\":1,\"livemode\":true,\"metadata\":{\"substack\":\"yes\"},\"meter\":null,\"nickname\":\"\u20AC74 a year\",\"product\":\"prod_R0QYUJf9xqVpaq\",\"tiers_mode\":null,\"transform_usage\":null,\"trial_period_days\":null,\"usage_type\":\"licensed\",\"currency_options\":{\"aud\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":12500,\"unit_amount_decimal\":\"12500\"},\"brl\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":43500,\"unit_amount_decimal\":\"43500\"},\"cad\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":12000,\"unit_amount_decimal\":\"12000\"},\"chf\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":7000,\"unit_amount_decimal\":\"7000\"},\"dkk\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":55500,\"unit_amount_decimal\":\"55500\"},\"eur\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":7400,\"unit_amount_decimal\":\"7400\"},\"gbp\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":6500,\"unit_amount_decimal\":\"6500\"},\"inr\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":811000,\"unit_amount_decimal\":\"811000\"},\"jpy\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":14000,\"unit_amount_decimal\":\"14000\"},\"mxn\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":148000,\"unit_amount_decimal\":\"148000\"},\"nok\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":81500,\"unit_amount_decimal\":\"81500\"},\"nzd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":15000,\"unit_amount_decimal\":\"15000\"},\"pln\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":32500,\"unit_amount_decimal\":\"32500\"},\"sek\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":82000,\"unit_amount_decimal\":\"82000\"},\"usd\":{\"custom_unit_amount\":null,\"tax_behavior\":\"unspecified\",\"unit_amount\":8500,\"unit_amount_decimal\":\"8500\"}}},{\"id\":\"founding20000eur\",\"name\":\"founding20000eur\",\"nickname\":\"founding20000eur\",\"active\":true,\"amount\":20000,\"currency\":\"eur\",\"interval\":\"year\",\"interval_count\":1,\"metadata\":{\"substack\":\"yes\",\"founding\":\"yes\",\"no_coupons\":\"yes\",\"short_description\":\"VIP supporter\",\"short_description_english\":\"VIP supporter\",\"minimum\":\"20000\",\"minimum_local\":{\"usd\":23500,\"gbp\":17500,\"eur\":20000,\"cad\":32500,\"mxn\":394000,\"aud\":32500,\"brl\":119000,\"sek\":225500,\"chf\":19000,\"dkk\":149500,\"nok\":215500,\"inr\":2217000,\"jpy\":36000,\"nzd\":40000,\"pln\":86500}},\"currency_options\":{\"usd\":{\"unit_amount\":23500,\"tax_behavior\":\"unspecified\"},\"gbp\":{\"unit_amount\":17500,\"tax_behavior\":\"unspecified\"},\"eur\":{\"unit_amount\":20000,\"tax_behavior\":\"unspecified\"},\"cad\":{\"unit_amount\":32500,\"tax_behavior\":\"unspecified\"},\"mxn\":{\"unit_amount\":394000,\"tax_behavior\":\"unspecified\"},\"aud\":{\"unit_amount\":32500,\"tax_behavior\":\"unspecified\"},\"brl\":{\"unit_amount\":119000,\"tax_behavior\":\"unspecified\"},\"sek\":{\"unit_amount\":225500,\"tax_behavior\":\"unspecified\"},\"chf\":{\"unit_amount\":19000,\"tax_behavior\":\"unspecified\"},\"dkk\":{\"unit_amount\":149500,\"tax_behavior\":\"unspecified\"},\"nok\":{\"unit_amount\":215500,\"tax_behavior\":\"unspecified\"},\"inr\":{\"unit_amount\":2217000,\"tax_behavior\":\"unspecified\"},\"jpy\":{\"unit_amount\":36000,\"tax_behavior\":\"unspecified\"},\"nzd\":{\"unit_amount\":40000,\"tax_behavior\":\"unspecified\"},\"pln\":{\"unit_amount\":86500,\"tax_behavior\":\"unspecified\"}}}],\"stripe_user_id\":\"acct_1MAFmbEv9TeVut3s\",\"stripe_country\":\"SE\",\"stripe_publishable_key\":\"pk_live_51MAFmbEv9TeVut3sg6LOLDoGpzdvqtqZvasczL18isiPGcezpoD3DRMPDmivD2Qu12m0h0mpKUgIqx5cJZisTK1500fjcalFnx\",\"stripe_platform_account\":\"US\",\"automatic_tax_enabled\":false,\"author_name\":\"Alex Ewerl\u00F6f\",\"author_handle\":\"alexewerlof\",\"author_photo_url\":\"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"author_bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"twitter_screen_name\":\"alexewerlof\",\"has_custom_tos\":false,\"has_custom_privacy\":false,\"theme\":{\"background_pop_color\":\"#FFBC52\",\"web_bg_color\":\"#001426\",\"cover_bg_color\":\"#001426\",\"publication_id\":1002265,\"color_links\":null,\"font_preset_heading\":\"sans\",\"font_preset_body\":\"fancy_serif\",\"font_family_headings\":null,\"font_family_body\":null,\"font_family_ui\":null,\"font_size_body_desktop\":null,\"print_secondary\":null,\"custom_css_web\":null,\"custom_css_email\":null,\"home_hero\":\"feature-media\",\"home_posts\":\"custom\",\"home_show_top_posts\":true,\"hide_images_from_list\":false,\"home_hero_alignment\":\"left\",\"home_hero_show_podcast_links\":true,\"default_post_header_variant\":null,\"custom_header\":{\"layout\":\"stacked\",\"navStyle\":\"text\",\"navPosition\":\"bottom\",\"wordmarkLogoSize\":42},\"custom_footer\":{\"layout\":\"two-column\",\"backgroundColor\":\"#000C17\",\"publicationNameSize\":50,\"showPublicationName\":false,\"publicationNameStyle\":\"text\",\"publicationNamePosition\":\"bottom\",\"publicationNameBackgroundColor\":null},\"social_media_links\":{\"bluesky\":\"https://bsky.app/profile/alexewerlof.com\",\"youtube\":\"https://www.youtube.com/@alexewerlof\",\"linkedin\":\"https://www.linkedin.com/in/alexewerlof/\"},\"font_options\":{\"body\":\"merriweather_400\",\"heading\":\"heavy_sans\"},\"section_template\":null,\"custom_subscribe\":null,\"design_template\":null,\"design_template_options\":null},\"threads_v2_settings\":{\"first_thread_email_sent_at\":\"2023-02-12T20:30:37.079+00:00\",\"activated_at\":\"2023-02-12T20:30:06.164+00:00\",\"reader_thread_notifications_enabled\":true,\"create_thread_minimum_role\":\"paid\",\"photo_replies_enabled\":true,\"boost_free_subscriber_chat_preview_enabled\":false,\"push_suppression_enabled\":false},\"default_group_coupon_percent_off\":\"50.00\",\"default_group_coupon_include_founding\":false,\"pause_return_date\":null,\"has_posts\":true,\"has_recommendations\":true,\"first_post_date\":\"2020-09-24T11:28:00.000Z\",\"has_podcast\":false,\"has_free_podcast\":false,\"has_subscriber_only_podcast\":false,\"has_community_content\":true,\"rankingDetail\":\"Launched 4 years ago\",\"rankingDetailFreeIncluded\":\"Tens of thousands of subscribers\",\"rankingDetailOrderOfMagnitude\":10,\"rankingDetailFreeIncludedOrderOfMagnitude\":10000,\"rankingDetailFreeSubscriberCount\":\"Over 19,000 subscribers\",\"rankingDetailByLanguage\":{\"ar\":{\"rankingDetail\":\"\u062A\u0645 \u0627\u0644\u0625\u0637\u0644\u0627\u0642 4 years ago\"},\"ca\":{\"rankingDetail\":\"S\u2019ha llan\u00E7at fa 4 anys\"},\"da\":{\"rankingDetail\":\"Lancering 4 \u00E5r\"},\"de\":{\"rankingDetail\":\"vor 4 Jahren gelauncht\"},\"es\":{\"rankingDetail\":\"Lanzado hace 4 a\u00F1os\"},\"fr\":{\"rankingDetail\":\"Lanc\u00E9 il y a 4 ann\u00E9es\"},\"id\":{\"rankingDetail\":\"Diluncurkan 4 tahun yang lalu\"},\"ja\":{\"rankingDetail\":\"\u958B\u59CB\u65E5 4\u5E74\u524D\"},\"ko\":{\"rankingDetail\":\"4\uB144 \uC804\uC5D0 \uCD9C\uC2DC\"},\"nb\":{\"rankingDetail\":\"Lansert 4 \u00E5r\"},\"nl\":{\"rankingDetail\":\"Gelanceerd 4 jaar geleden\"},\"pl\":{\"rankingDetail\":\"Uruchomiono 4 lat temu\"},\"pt\":{\"rankingDetail\":\"Lan\u00E7ado 4 anos\"},\"pt-br\":{\"rankingDetail\":\"Lan\u00E7ado 4 anos\"},\"en-gb\":{\"rankingDetail\":\"Launched 4 years ago\"},\"it\":{\"rankingDetail\":\"Lanciato 4 anni\"},\"tr\":{\"rankingDetail\":\"4 y\u0131l ba\u015Flat\u0131ld\u0131\"},\"sv\":{\"rankingDetail\":\"Lanserad 4 \u00E5r sedan\"},\"fi\":{\"rankingDetail\":\"Launched 4 vuotta\"},\"is\":{\"rankingDetail\":\"Launched 4 \u00E1r\"},\"zh-hans\":{\"rankingDetail\":\"\u4E8E4 \u5E74\u524D\u4E0A\u7EBF\"},\"zh-hant\":{\"rankingDetail\":\"\u65BC 4 \u5E74\u524D \u63A8\u51FA\"},\"en\":{\"rankingDetail\":\"Launched 4 years ago\"}},\"freeSubscriberCount\":\"19,000\",\"freeSubscriberCountOrderOfMagnitude\":\"19K+\",\"author_bestseller_tier\":0,\"author_badge\":null,\"disable_monthly_subscriptions\":false,\"disable_annual_subscriptions\":false,\"hide_post_restacks\":false,\"notes_feed_enabled\":true,\"showIntroModule\":false,\"isPortraitLayout\":false,\"last_chat_post_at\":\"2025-10-31T11:34:19.438Z\",\"primary_profile_name\":\"Alex Ewerl\u00F6f\",\"primary_profile_photo_url\":\"https://substackcdn.com/image/fetch/$s_!IRtW!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"no_follow\":false,\"sponsorshipCampaigns\":{},\"paywall_chat\":\"free\",\"sections\":[{\"id\":67726,\"created_at\":\"2023-05-31T20:13:23.606Z\",\"updated_at\":\"2024-11-12T15:54:54.980Z\",\"publication_id\":1002265,\"name\":\"Technical Leadership\",\"description\":\"Technical Leadership, Staff Engineering, and impact without mandate\",\"slug\":\"tech-lead\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":0,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51608,\"publication_id\":1002265,\"section_id\":67726,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":69986,\"created_at\":\"2023-06-17T13:00:28.926Z\",\"updated_at\":\"2023-06-17T13:00:28.926Z\",\"publication_id\":1002265,\"name\":\"Growth\",\"description\":\"Growth mindset, productivity, organizational growth, culture\",\"slug\":\"growth\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":2,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51610,\"publication_id\":1002265,\"section_id\":69986,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":65305,\"created_at\":\"2023-05-14T08:17:44.620Z\",\"updated_at\":\"2023-05-14T08:17:44.620Z\",\"publication_id\":1002265,\"name\":\"Cartoons\",\"description\":\"The cartoons and doodles I draw from time to time\",\"slug\":\"cartoons\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":3,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51611,\"publication_id\":1002265,\"section_id\":65305,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null},{\"id\":192721,\"created_at\":\"2025-02-23T16:44:05.979Z\",\"updated_at\":\"2025-02-23T16:44:09.931Z\",\"publication_id\":1002265,\"name\":\"Code\",\"description\":\"Code and software development\",\"slug\":\"code\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":4,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51612,\"publication_id\":1002265,\"section_id\":192721,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}],\"podcastTabInfo\":null,\"multipub_migration\":null,\"navigationBarItems\":[{\"id\":\"693b47dd-b5e5-4dbb-b7b3-891c9b2c1835\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":false,\"standard_key\":\"about\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"52ced5af-109a-4b1e-8910-89961a72b0a3\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"leaderboard\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"5657cede-0e4c-4869-8f2d-c73ebe2b3338\",\"publication_id\":1002265,\"sibling_rank\":0,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"notes\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"d020acfa-0f0b-4afb-a793-8626297a59aa\",\"publication_id\":1002265,\"sibling_rank\":1,\"link_title\":null,\"link_url\":null,\"section_id\":null,\"post_id\":null,\"is_hidden\":true,\"standard_key\":\"chat\",\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":null},{\"id\":\"fc613bc6-10ab-41ef-9d39-a6a818fbb5ba\",\"publication_id\":1002265,\"sibling_rank\":2,\"link_title\":null,\"link_url\":null,\"section_id\":67726,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":67726,\"slug\":\"tech-lead\",\"name\":\"Technical Leadership\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"68d82a75-97a1-498b-b089-b9d606ee0f27\",\"publication_id\":1002265,\"sibling_rank\":3,\"link_title\":null,\"link_url\":null,\"section_id\":67723,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":67723,\"slug\":\"sre\",\"name\":\"Reliability Engineering\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"8a522501-651b-45bc-b881-3e2a2497ec29\",\"publication_id\":1002265,\"sibling_rank\":4,\"link_title\":null,\"link_url\":null,\"section_id\":69986,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":69986,\"slug\":\"growth\",\"name\":\"Growth\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"702039d0-d1f1-4070-adb7-6a88110ac904\",\"publication_id\":1002265,\"sibling_rank\":5,\"link_title\":null,\"link_url\":null,\"section_id\":65305,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":65305,\"slug\":\"cartoons\",\"name\":\"Cartoons\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}},{\"id\":\"71e27c1f-1d9d-486d-bcce-3b707aedb0f6\",\"publication_id\":1002265,\"sibling_rank\":8,\"link_title\":\"FAQ\",\"link_url\":\"\",\"section_id\":null,\"post_id\":141786627,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":{\"id\":141786627,\"slug\":\"faq\",\"title\":\"FAQ\",\"type\":\"page\"},\"section\":null},{\"id\":\"c3e7d81f-5147-498f-8317-72f318b996c3\",\"publication_id\":1002265,\"sibling_rank\":9999,\"link_title\":null,\"link_url\":null,\"section_id\":192721,\"post_id\":null,\"is_hidden\":null,\"standard_key\":null,\"post_tag_id\":null,\"parent_id\":null,\"is_group\":false,\"postTag\":null,\"children\":[],\"post\":null,\"section\":{\"id\":192721,\"slug\":\"code\",\"name\":\"Code\",\"hide_from_navbar\":false,\"is_podcast\":false,\"logo_url\":null,\"newsletter_enabled\":null}}],\"has_active_perks\":false,\"contributors\":[{\"name\":\"Alex Ewerl\u00F6f\",\"handle\":\"alexewerlof\",\"role\":\"admin\",\"owner\":true,\"user_id\":87732486,\"photo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"status\":{\"bestsellerTier\":null,\"subscriberTier\":null,\"leaderboard\":null,\"vip\":false,\"badge\":null,\"subscriber\":null}}],\"threads_v2_enabled\":true,\"viralGiftsConfig\":{\"id\":\"549946e0-1129-4592-ba5f-6bcab8c6cb5d\",\"publication_id\":1002265,\"enabled\":true,\"gifts_per_user\":5,\"gift_length_months\":1,\"send_extra_gifts\":true,\"message\":\"Technical Leadership, personal growth, software\",\"created_at\":\"2022-12-01T16:46:31.467333+00:00\",\"updated_at\":\"2022-12-01T16:46:31.467333+00:00\",\"days_til_invite\":14,\"send_emails\":true,\"show_link\":null},\"no_index\":false,\"tier\":2,\"can_set_google_site_verification\":true,\"can_have_sitemap\":true,\"iap_advanced_plans\":[{\"sku\":\"c1LuwhX14kmFN5UK5J\",\"publication_id\":\"1002265\",\"is_active\":true,\"price_base_units\":1200,\"currency_alpha3\":\"usd\",\"period\":\"month\",\"created_at\":\"2026-07-07T19:37:06.872Z\",\"updated_at\":\"2026-07-07T19:37:06.872Z\",\"id\":\"1272592\",\"payout_amount_base_units\":86,\"alternate_currencies\":{\"aud\":1800,\"brl\":6500,\"cad\":1800,\"chf\":1000,\"dkk\":8000,\"eur\":1100,\"gbp\":900,\"mxn\":21000,\"nok\":12000,\"nzd\":2200,\"pln\":4500,\"sek\":12000},\"is_founding\":false,\"display_name\":\"Alex Ewerl\u00F6f Notes (Monthly)\",\"display_price\":\"$12\"},{\"sku\":\"MC73cNbFZtu7O35fUc\",\"publication_id\":\"1002265\",\"is_active\":true,\"price_base_units\":11500,\"currency_alpha3\":\"usd\",\"period\":\"year\",\"created_at\":\"2026-07-07T19:37:06.880Z\",\"updated_at\":\"2026-07-07T19:37:06.880Z\",\"id\":\"1272593\",\"payout_amount_base_units\":847,\"alternate_currencies\":{\"aud\":17000,\"brl\":59500,\"cad\":16500,\"chf\":9500,\"dkk\":75500,\"eur\":10500,\"gbp\":9000,\"mxn\":200000,\"nok\":112500,\"nzd\":20500,\"pln\":43500,\"sek\":111000},\"is_founding\":false,\"display_name\":\"Alex Ewerl\u00F6f Notes (Yearly)\",\"display_price\":\"$115\"}],\"iap_founding_plan\":{\"base_plan_id\":\"founding20000eur\",\"name\":\"VIP supporter\",\"minimum_amount\":27500,\"suggested_amount\":27500,\"currency_alpha3\":\"usd\",\"alternate_currencies\":{\"gbp\":{\"minimum_amount\":20500,\"suggested_amount\":20500},\"eur\":{\"minimum_amount\":24000,\"suggested_amount\":24000},\"cad\":{\"minimum_amount\":38500,\"suggested_amount\":38500},\"mxn\":{\"minimum_amount\":467000,\"suggested_amount\":467000},\"aud\":{\"minimum_amount\":38500,\"suggested_amount\":38500},\"brl\":{\"minimum_amount\":141000,\"suggested_amount\":141000},\"sek\":{\"minimum_amount\":267000,\"suggested_amount\":267000},\"chf\":{\"minimum_amount\":22500,\"suggested_amount\":22500},\"dkk\":{\"minimum_amount\":177500,\"suggested_amount\":177500},\"nok\":{\"minimum_amount\":255500,\"suggested_amount\":255500},\"inr\":{\"minimum_amount\":2628500,\"suggested_amount\":2628500},\"jpy\":{\"minimum_amount\":42500,\"suggested_amount\":42500},\"nzd\":{\"minimum_amount\":47500,\"suggested_amount\":47500},\"pln\":{\"minimum_amount\":103000,\"suggested_amount\":103000}}},\"founding_plan_name_english\":\"VIP supporter\",\"base_url\":\"https://blog.alexewerlof.com\",\"hostname\":\"blog.alexewerlof.com\",\"is_on_substack\":false,\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null,\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"pageThemes\":{\"podcast\":null},\"supports_ip_content_unlock\":false,\"appTheme\":{\"colors\":{\"accent\":{\"name\":\"#ffbc52\",\"primary\":{\"r\":222,\"g\":158,\"b\":52,\"a\":1},\"primary_hover\":{\"r\":201,\"g\":140,\"b\":31,\"a\":1},\"primary_elevated\":{\"r\":201,\"g\":140,\"b\":31,\"a\":1},\"secondary\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.2},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.2},\"bg_hover\":{\"r\":222,\"g\":158,\"b\":52,\"a\":0.3},\"dark\":{\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":210,\"b\":125,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":210,\"b\":125,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.2},\"contrast\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.8},\"bg\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":188,\"b\":82,\"a\":0.3}}},\"fg\":{\"primary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.8},\"secondary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.6},\"tertiary\":{\"r\":0,\"g\":0,\"b\":0,\"a\":0.4},\"accent\":{\"r\":151,\"g\":97,\"b\":0,\"a\":1},\"dark\":{\"primary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.9},\"secondary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.6},\"tertiary\":{\"r\":255,\"g\":255,\"b\":255,\"a\":0.4},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1}}},\"bg\":{\"name\":\"#0085e5\",\"hue\":{\"r\":0,\"g\":133,\"b\":229,\"a\":1},\"tint\":{\"r\":0,\"g\":133,\"b\":229,\"a\":0.1},\"primary\":{\"r\":229.5,\"g\":242.8,\"b\":252.39999999999998,\"a\":1},\"primary_hover\":{\"r\":225,\"g\":238.29999999999998,\"b\":247.9,\"a\":1},\"primary_elevated\":{\"r\":225,\"g\":238.29999999999998,\"b\":247.9,\"a\":1},\"secondary\":{\"r\":214.2,\"g\":227.5,\"b\":237.1,\"a\":1},\"secondary_elevated\":{\"r\":184.9454280083347,\"g\":197.91521411644928,\"b\":207.26517218866366,\"a\":1},\"tertiary\":{\"r\":197.1,\"g\":210.4,\"b\":219.99999999999997,\"a\":1},\"quaternary\":{\"r\":163.79999999999998,\"g\":177.10000000000002,\"b\":186.70000000000002,\"a\":1},\"dark\":{\"primary\":{\"r\":19.8,\"g\":34,\"b\":44.5,\"a\":1},\"primary_hover\":{\"r\":24.3,\"g\":38.50000000000001,\"b\":48.99999999999999,\"a\":1},\"primary_elevated\":{\"r\":24.3,\"g\":38.50000000000001,\"b\":48.99999999999999,\"a\":1},\"secondary\":{\"r\":31.5,\"g\":46.60000000000001,\"b\":56.2,\"a\":1},\"secondary_elevated\":{\"r\":38.73972711589789,\"g\":54.076229834048654,\"b\":63.89709451363946,\"a\":1},\"tertiary\":{\"r\":48.6,\"g\":62.8,\"b\":72.4,\"a\":1},\"quaternary\":{\"r\":81.00000000000001,\"g\":95.2,\"b\":104.80000000000001,\"a\":1}}}}},\"portalAppTheme\":{\"colors\":{\"accent\":{\"name\":\"#FFBC52\",\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":178,\"b\":56,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.3},\"dark\":{\"name\":\"#FFBC52\",\"primary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"primary_hover\":{\"r\":255,\"g\":178,\"b\":56,\"a\":1},\"primary_elevated\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"secondary\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"contrast\":{\"r\":255,\"g\":255,\"b\":255,\"a\":1},\"bg\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.2},\"bg_hover\":{\"r\":255,\"g\":103,\"b\":25,\"a\":0.3}}},\"fg\":{\"primary\":{\"r\":226,\"g\":232,\"b\":237,\"a\":1},\"secondary\":{\"r\":153,\"g\":161,\"b\":168,\"a\":1},\"tertiary\":{\"r\":109,\"g\":120,\"b\":130,\"a\":1},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1},\"dark\":{\"primary\":{\"r\":226,\"g\":232,\"b\":237,\"a\":1},\"secondary\":{\"r\":153,\"g\":161,\"b\":168,\"a\":1},\"tertiary\":{\"r\":109,\"g\":120,\"b\":130,\"a\":1},\"accent\":{\"r\":255,\"g\":188,\"b\":82,\"a\":1}}},\"bg\":{\"name\":\"#001426\",\"hue\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"tint\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary_hover\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"primary_elevated\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary_elevated\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"tertiary\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"quaternary\":{\"r\":72,\"g\":86,\"b\":99,\"a\":1},\"dark\":{\"name\":\"#001426\",\"hue\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"tint\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"primary_hover\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"primary_elevated\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary\":{\"r\":15,\"g\":34,\"b\":51,\"a\":1},\"secondary_elevated\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"tertiary\":{\"r\":34,\"g\":52,\"b\":67,\"a\":1},\"quaternary\":{\"r\":72,\"g\":86,\"b\":99,\"a\":1}}},\"wordmark_bg\":{\"r\":0,\"g\":20,\"b\":38,\"a\":1},\"is_dark\":true},\"fonts\":{\"heading\":\"heavy_sans\",\"body\":\"merriweather_400\"}},\"logoPalette\":{\"Vibrant\":{\"rgb\":[252,188,84],\"population\":5509},\"DarkVibrant\":{\"rgb\":[4,20,36],\"population\":556},\"LightVibrant\":{\"rgb\":[244,181,84],\"population\":7},\"Muted\":{\"rgb\":[124,100,60],\"population\":1},\"DarkMuted\":{\"rgb\":[80,71,52],\"population\":65},\"LightMuted\":{\"rgb\":[143.75274725274724,90.7912087912088,9.247252747252743],\"population\":0}},\"section\":{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}},\"confirmedLogin\":false,\"hide_intro_popup\":false,\"block_auto_login\":false,\"domainInfo\":{\"isSubstack\":false,\"customDomain\":\"blog.alexewerlof.com\"},\"experimentFeatures\":{},\"experimentExposures\":{},\"siteConfigs\":{\"score_upsell_email\":\"control\",\"first_chat_email_enabled\":true,\"new_commenter_approval\":false,\"pub_update_opennode_api_key\":false,\"notes_video_max_duration_minutes\":15,\"show_content_label_age_gating_in_feed\":false,\"zendesk_automation_cancellations\":false,\"mfa_action_box_enabled\":false,\"publication_max_bylines\":35,\"no_contest_charge_disputes\":false,\"scheduled_post_share_assets_enabled\":false,\"publication_tabs_reorder\":false,\"comp_expiry_email_new_copy\":\"NONE\",\"free_unlock_required\":false,\"enable_section_group_pages\":false,\"enable_post_summarization\":false,\"live_stream_host_warning_message\":\"\",\"bitcoin_enabled\":false,\"minimum_ios_os_version\":\"17.0.0\",\"show_entire_square_image\":false,\"hide_subscriber_count\":false,\"fit_in_live_stream_player\":false,\"publication_author_display_override\":\"\",\"enable_saved_segments\":true,\"generate_pdf_tax_report\":false,\"hide_post_sidebar\":false,\"show_generic_post_importer\":false,\"enable_pledges_modal\":true,\"community_automod_non_english_enabled\":true,\"audio_clips_enabled\":false,\"enable_videos_page\":false,\"exempt_from_gtm_filter\":false,\"group_sections_and_podcasts_in_menu\":false,\"boost_optin_modal_enabled\":true,\"standards_and_enforcement_features_enabled\":false,\"pub_creation_captcha_behavior\":\"risky_pubs_or_rate_limit\",\"post_blogspot_importer\":false,\"enable_high_res_background_uploading\":false,\"pub_tts_override\":\"default\",\"disable_monthly_subscriptions\":false,\"skip_welcome_email\":false,\"chat_reader_thread_notification_default\":false,\"scheduled_pinned_posts\":false,\"disable_redirect_outbound_utm_params\":false,\"reader_gift_referrals_enabled\":true,\"dont_show_guest_byline\":false,\"like_comments_enabled\":true,\"enable_theme_editor_deferred_saves\":false,\"enable_sponsorship_campaigns_advanced\":false,\"temporal_livestream_ended_draft\":true,\"enable_pangram_ai_detection\":true,\"fallback_to_archive_search_on_section_pages\":false,\"livekit_track_egress_custom_base_url\":\"http://livekit-egress-custom-recorder-participant-test.s3-website-us-east-1.amazonaws.com\",\"welcome_screen_blurb_override\":\"\",\"like_posts_enabled\":true,\"twitter_player_card_enabled\":true,\"feed_promoted_user\":false,\"show_note_stats_for_all_notes\":false,\"section_specific_csv_imports_enabled\":false,\"disable_podcast_feed_description_cta\":false,\"bypass_profile_substack_logo_detection\":false,\"use_preloaded_player_sources\":false,\"list_pruning_enabled\":false,\"facebook_connect\":false,\"opt_in_to_sections_during_subscribe\":false,\"underlined_colored_links\":false,\"enable_efficient_digest_embed\":false,\"enable_aligned_images\":false,\"max_image_upload_mb\":64,\"threads_suggested_ios_version\":null,\"pledges_disabled\":false,\"threads_minimum_ios_version\":812,\"hide_podcast_email_setup_link\":false,\"subscribe_captcha_behavior\":\"default\",\"publication_ban_sample_rate\":0,\"custom_themes_substack_subscribe_modal\":false,\"ios_post_share_assets_screenshot_trigger\":\"control\",\"opt_in_to_sections_during_subscribe_include_main_pub_newsletter\":false,\"continue_support_cta_in_newsletter_emails\":false,\"bloomberg_syndication_enabled\":false,\"allow_document_freeze\":false,\"test_age_gate_user\":false,\"podcast_main_feed_is_firehose\":false,\"pub_app_incentive_gift\":\"\",\"no_embed_redirect\":false,\"customized_email_from_name_for_new_follow_emails\":\"treatment\",\"spotify_open_access_sandbox_mode\":false,\"disable_custom_nav_menu\":false,\"enable_livestream_name_cards\":false,\"fullstory_enabled\":false,\"chat_reply_poll_interval\":3,\"thefp_enable_email_upsell_banner\":false,\"force_pub_links_to_use_subdomain\":false,\"always_show_cookie_banner\":false,\"hide_media_download_option\":false,\"hide_post_restacks\":false,\"feed_item_source_debug_mode\":false,\"twitter_embed_video_playback_enabled\":false,\"publication_homepage_title_display_override\":\"\",\"enable_email_automation_stats\":false,\"post_preview_highlight_byline\":false,\"4k_video\":false,\"enable_islands_section_intent_screen\":false,\"post_metering_enabled\":false,\"notifications_disabled\":\"\",\"cross_post_notification_threshold\":1000,\"facebook_connect_prod_app\":true,\"force_into_pymk_ranking\":false,\"minimum_android_version\":756,\"group_size_change_notification_email_enabled\":false,\"enable_transcription_translations\":false,\"use_og_image_as_twitter_image_for_post_previews\":false,\"always_use_podcast_channel_art_as_episode_art_in_rss\":false,\"seo_tier_override\":\"NONE\",\"editor_role_enabled\":false,\"no_follow_links\":false,\"publisher_api_enabled\":false,\"zendesk_support_priority\":\"default\",\"enable_post_clips_stats\":false,\"enable_subscriber_referrals_awards\":true,\"ios_profile_themes_feed_permalink_enabled\":false,\"reader_survey_during_subscribe_enabled\":true,\"use_publication_language_for_transcription\":false,\"show_substack_funded_gifts_tooltip\":true,\"disable_ai_transcription\":false,\"per_pub_notification_settings\":false,\"live_stream_creation_enabled\":true,\"disable_card_element_in_europe\":false,\"web_growth_item_promotion_threshold\":0,\"bundle_subscribe_enabled\":false,\"web_vitals_sample_rate\":0,\"allow_live_stream_auto_takedown\":\"true\",\"mobile_publication_attachments_enabled\":false,\"enable_design_templates_events_page\":false,\"enable_survey_response_crm_filters\":false,\"disable_personal_substack_initialization\":false,\"section_specific_welcome_pages\":false,\"local_payment_methods\":\"control\",\"publisher_api_cancel_comp\":false,\"posts_in_rss_feed\":20,\"publisher_dashboard_section_selector\":false,\"reader_surveys_platform_question_order\":\"36,1,4,2,3,5,6,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35\",\"login_guard_app_link_in_email\":true,\"community_moderators_enabled\":false,\"enable_custom_theme\":false,\"monthly_sub_is_one_off\":false,\"unread_notes_activity_digest\":\"control\",\"display_cookie_settings\":false,\"welcome_page_query_params\":false,\"enable_free_podcast_urls\":false,\"comp_expiry_emails_disabled\":false,\"enable_description_on_polls\":false,\"use_microlink_for_instagram_embeds\":false,\"free_signup_confirmation_behavior\":\"with_email_validation\",\"ios_post_stats_for_admins\":false,\"enable_design_templates\":false,\"use_livestream_post_media_composition\":true,\"section_specific_preambles\":false,\"pub_export_temp_disable\":false,\"show_menu_on_posts\":false,\"ios_post_subscribe_web_routing\":true,\"enable_pangram_detection_settings\":false,\"freewalls_enabled_web\":false,\"app_onboarding_survey_email\":false,\"republishing_enabled\":false,\"app_mode\":false,\"show_phone_banner\":false,\"minimum_ios_version\":2200,\"enable_author_pages\":false,\"enable_decagon_chat\":true,\"first_month_upsell\":\"control\",\"new_user_checklist_enabled\":\"use_follower_count\",\"disable_high_res_recording\":false,\"latex_upgraded_inline\":false,\"anonymous_post_metering_enabled\":false,\"rss_verification_code\":\"\",\"notification_post_emails\":\"experiment\",\"chat_suppress_contributor_push_option_enabled\":false,\"enable_subscriber_tags\":true,\"media_feed_app_prepend_inbox_limit\":0,\"export_hooks_enabled\":false,\"audio_encoding_bitrate\":null,\"extra_seats_coupon_type\":false,\"post_subdomain_universal_links\":false,\"post_import_max_file_size\":26214400,\"feed_promoted_video_publication\":false,\"livekit_reconnect_slate_url\":\"https://mux-livestream-assets.s3.us-east-1.amazonaws.com/custom-disconnect-slate-tall.png\",\"exclude_from_pymk_suggestions\":false,\"publication_ranking_variant\":\"experiment\",\"disable_annual_subscriptions\":false,\"hack_jane_manchun_wong\":true,\"android_enable_auto_gain_control\":true,\"allow_coupons_on_upgrade\":false,\"test_au_age_gate_user\":false,\"pub_auto_moderation_enabled\":false,\"disable_live_stream_ai_trimming_by_default\":false,\"disable_deletion\":false,\"livekit_egress_custom_base_url\":\"http://livekit-egress-custom-recorder.s3-website-us-east-1.amazonaws.com\",\"clip_focused_video_upload_flow\":false,\"live_stream_max_guest_users\":2,\"android_upgrade_alert_dialog_reincarnated\":true,\"enable_video_seo_data\":false,\"can_reimport_unsubscribed_users_with_2x_optin\":false,\"founding_upgrade_during_gift_disabled\":false,\"thefp_enable_section_groups\":false,\"review_incoming_email\":\"default\",\"enable_founding_gifts\":false,\"enable_sponsorship_campaigns\":false,\"thefp_forum_polls_enabled\":false,\"thefp_enable_embed_media_links\":false,\"sort_modal_search_results\":false,\"default_thumbnail_time\":10,\"load_test_unichat\":false,\"live_stream_head_alignment_guide\":false,\"free_press_combo_subscribe_flow_enabled\":false,\"enable_code_embed_toc\":false,\"enable_publication_tax_settings\":false,\"gifts_from_substack_feature_available\":true,\"disable_ai_clips\":false,\"enable_elevenlabs_voiceovers\":false,\"thefp_enable_transcripts\":false,\"show_simple_post_editor\":false,\"instacart_integration_enabled\":false,\"enable_publication_podcasts_page\":false,\"enable_direct_message_request_bypass\":false,\"enable_apple_news_sync\":false,\"live_stream_in_trending_topic_overrides\":\"\",\"free_press_newsletter_promo_enabled\":false,\"account_based_post_metering_enabled\":false,\"disable_live_stream_reactions\":false,\"instacart_partner_id\":\"\",\"enable_adhoc_email_scheduling\":true,\"media_feed_prepend_inbox_limit\":35,\"welcome_page_no_opt_out\":false,\"enable_caption_translation_tools\":false,\"section_specific_postscripts\":false,\"edit_profile_theme_colors\":false,\"disable_clipping_for_readers\":false,\"enable_apple_podcast_delivery_self_serve_pem_files\":false,\"enable_press_kit_preview_modal\":false,\"enable_rnc_page\":true,\"live_stream_video_degradation_preference\":\"maintainFramerate\",\"enable_high_follower_dm\":true,\"pause_app_badges\":false,\"profile_feed_expanded_inventory\":false,\"livekit_mux_latency_mode\":\"low\",\"feed_juiced_user\":0,\"global_iap_plan_setup_countries\":\"AE,AG,AL,AM,AT,AU,BA,BG,BH,BJ,BN,BS,BT,BW,CH,CI,CR,CY,CZ,DK,DZ,EC,EE,ET,FI,GM,GT,GY,HK,HR,HU,ID,IL,IN,IS,JM,JO,KE,KW,LC,LI,LK,LT,LU,LV,MA,MD,MG,MK,MN,MT,MU,MX,MY,MZ,NA,NO,NZ,OM,PA,PE,PH,PK,QA,RO,RS,RW,SE,SG,SI,SK,SN,SV,TH,TN,TR,TT,TW,TZ,UZ,VN,ZA\",\"enable_collapsed_content\":false,\"enable_polymarket_expandable_embeds\":true,\"publisher_dashboard_group_subs_sidebar\":false,\"use_advanced_commerce_api_for_iap\":false,\"skip_free_preview_language_in_podcast_notes\":false,\"larger_wordmark_on_publication_homepage\":false,\"enable_mobile_stats_for_admins\":false,\"enable_livestream_youtube_simulcast\":false,\"enable_persona_sandbox_environment\":false,\"allowed_email_domains\":\"mozmail.com\",\"create_nav_item_from_tag\":false,\"bypass_single_unlock_token_limit\":false,\"enable_code_embeds\":false,\"add_section_and_tag_metadata\":false,\"daily_promoted_notes_enabled\":true,\"enable_segments_ui_revamp\":true,\"enable_islands_cms\":false,\"enable_livestream_combined_stats\":false,\"redirect_to_pub_after_welcome_signup\":false,\"chartbeat_video_enabled\":false,\"enable_drip_campaigns\":false,\"enable_filtered_posts_on_homepage\":false,\"post_management_search_engine\":\"elasticsearch\",\"new_bestseller_leaderboard_feed_item_enabled\":false,\"feed_main_disabled\":false,\"enable_account_settings_revamp\":false,\"thefp_enable_fp_recirc_block\":false,\"top_search_variant\":\"control\",\"enable_debug_logs_ios\":false,\"show_pub_content_on_profile_for_pub_id\":0,\"show_pub_content_on_profile\":false,\"livekit_track_egress\":true,\"onboarding_suggestions_search\":\"experiment\",\"feed_tuner_enabled\":false,\"livekit_mux_latency_mode_rtmp\":\"low\",\"google_login_enabled\":false,\"livekit_high_quality_egress\":false,\"iap_announcement_blog_url\":\"\",\"disable_code_embed_chrome\":false,\"ios_livestream_feedback\":false,\"founding_plan_upgrade_warning\":false,\"ios_mediaplayer_reply_bar_v2\":false,\"enable_notification_email_batching\":true,\"note_author_poll_results_visible_by_default\":true,\"ios_hide_portal_tab_bar\":false,\"follow_upsell_rollout_percentage\":30,\"gift_article_enabled\":false,\"live_stream_invite_ttl_seconds\":900000,\"include_founding_plans_coupon_option\":false,\"thefp_enable_cancellation_discount_offer\":false,\"android_enable_edit_profile_theme\":false,\"disable_audio_enhancement\":false,\"pub_search_variant\":\"control\",\"ignore_video_in_notes_length_limit\":false,\"substack_gtm_enabled\":false,\"allow_long_videos\":true,\"enable_automation_filters\":false,\"use_enhanced_video_embed_player\":true,\"founding_upgrade_preview\":false,\"enable_viewing_all_livestream_viewers\":false,\"send_subscription_canceled_email\":false,\"enable_clip_prompt_variant_filtering\":true,\"chartbeat_enabled\":false,\"dpn_ranking_enabled\":true,\"enable_custom_email_css\":false,\"thefp_enable_shows_page\":false,\"enable_apple_podcast_auto_publish\":false,\"linkedin_profile_search_enabled\":false,\"publication_has_own_app\":false,\"suggested_minimum_ios_version\":0,\"thebulwark_enable_footer_actions\":false,\"enable_posts_to_segments\":true,\"trending_topics_module_long_term_experiment\":\"control\",\"phone_verification_fallback_to_twilio\":false,\"enable_suggested_searches\":true,\"enable_subscription_notification_email_batching\":true,\"feed_controls\":\"control\",\"thefp_enable_plans_modal_v2\":false,\"a24_redemption_link\":\"\",\"design_templates_launch_phase\":\"off\",\"post_custom_email_from_name_enabled\":false,\"ios_live_stream_auto_gain_enabled\":true,\"enable_publication_tts_player\":false,\"enable_group_direct_messages\":true,\"enable_notes_admins\":false,\"thefp_show_pub_app_callout_on_post\":false,\"search_ranker_variant\":\"experiment\",\"forced_featured_topic_id\":\"\",\"ios_audio_captions_disabled\":false,\"web_podcasts_tab\":false,\"related_posts_enabled\":false,\"thefp_enable_homepage_secondary_nav\":false,\"ios_live_stream_pip_dismiss_v4\":\"control\",\"reply_rate_limit_max_distinct_users_daily\":110,\"web_post_metering_enabled\":true,\"search_retrieval_variant\":\"experiment\",\"mobile_user_attachments_enabled\":false,\"web_profile_publication_recommendations_carousel\":true,\"publisher_banner\":\"\",\"enable_sponsorship_profile\":false,\"gift_article_button_enabled\":false,\"reply_rate_limit_max_distinct_users_monthly\":600,\"desktop_live_stream_screen_share_audio_enabled\":false,\"creator_match\":true,\"ai_image_generation_enabled\":true,\"ios_default_coupon_enabled\":true,\"automod_admin_hidden_comments_tab\":true,\"video_clip_suggestions_enabled\":false,\"publisher_dashboard_home_layout_experiment\":\"control\",\"android_polymarket_embed_search\":false,\"audience_section_editor_help_link\":\"https://support.substack.com/hc/en-us/articles/50558240901268-How-do-I-add-audience-specific-content-to-a-post-on-Substack\",\"portal_ranking_variant\":\"experiment\",\"permalink_reply_ranking_variant\":\"experiment\",\"allow_feed_category_filtering\":false,\"enable_dynamic_content\":true,\"enable_thumbnail_editor_media_settings_integration\":false,\"subscriber_profile_survey_responses_enabled\":true,\"private_live_streaming_enabled\":true,\"desktop_live_stream_safe_framing\":0.8,\"translate_posts_on_standalone_sites\":true,\"bundle_subscribe_default_to_regular_plan\":false,\"enable_standardized_sponsorship_formats\":false,\"enable_pencraft_signin_form\":true,\"thefp_enable_secondary_section_redesign\":false,\"bignight_page_enabled\":true,\"thefp_paywall_annual_plans_experiment\":\"control\",\"enable_launch_assistant\":false,\"enable_youtube_exploration\":true,\"publisher_dashboard_nav_refresh\":false,\"thefp_enable_bundle_post_follow\":false,\"web_notes_tiptap_v3_experiment\":\"treatment_tiptap_v3\",\"recipe_rich_text_enabled\":true,\"publisher_dashboard_nav_refresh_experiment\":\"treatment\",\"chat_channel_creation_enabled\":false,\"web_onboarding_content_type_preferences\":\"experiment\",\"web_mobile_asset_handoff\":false},\"trackingTokens\":{\"fbPixelId\":null,\"gaPixelId\":null,\"twitterPixelId\":null,\"parselyPixelId\":null,\"googleTagManagerToken\":\"\",\"googleAnalytics4Token\":\"G-G8RXW18CW7\",\"twitterPixelSignupEventId\":null,\"twitterPixelSubscribeEventId\":null},\"publicationSettings\":{\"block_ai_crawlers\":false,\"credit_token_enabled\":true,\"custom_tos_and_privacy\":false,\"did_identity\":null,\"disable_optimistic_bank_payments\":false,\"display_welcome_page_details\":true,\"payment_pledges_enabled\":false,\"enable_drop_caps\":false,\"enable_post_page_conversion\":true,\"enable_prev_next_nav\":false,\"enable_restacking\":false,\"founding_group_subscriptions_enabled\":false,\"gifts_from_substack_disabled\":false,\"google_analytics_4_token\":\"G-G8RXW18CW7\",\"group_sections_and_podcasts_in_menu_enabled\":false,\"live_stream_homepage_visibility\":\"contributorsAndAdmins\",\"live_stream_homepage_style\":\"autoPlay\",\"live_stream_replay_enabled\":true,\"medium_length_description\":\"Senior Staff Engineer distilling 2+ decades of experience in System Reliability Engineering, Technical Leadership, and growth\",\"notes_feed_enabled\":true,\"paywall_unlock_tokens\":true,\"post_preview_crop_gravity\":\"center\",\"post_preview_radius\":\"xs\",\"reader_referrals_enabled\":true,\"reader_referrals_leaderboard_enabled\":true,\"seen_coming_soon_explainer\":false,\"seen_google_analytics_migration_modal\":false,\"local_currency_modal_seen\":true,\"local_payment_methods_modal_seen\":true,\"twitter_pixel_signup_event_id\":null,\"twitter_pixel_subscribe_event_id\":null,\"use_inclusive_sales_tax\":false,\"use_local_currency\":true,\"welcome_page_opt_out_text\":\"Maybe Later\",\"cookie_settings\":\"\",\"show_restacks_below_posts\":true,\"holiday_gifting_post_header\":true,\"homepage_message_text\":\"\",\"homepage_message_link\":\"\",\"about_us_author_ids\":\"\",\"archived_section_ids\":\"\",\"column_section_ids\":\"\",\"fp_primary_column_section_ids\":\"\",\"event_section_ids\":\"\",\"podcasts_metadata\":\"\",\"video_section_ids\":\"\",\"post_metering_enabled\":false,\"account_based_post_metering_enabled\":false,\"use_custom_theme\":false,\"reply_rules\":null,\"automatic_moderation_enabled\":true,\"auto_translate_enabled\":true,\"additional_post_languages_enabled\":false,\"high_res_recording_beta\":false},\"publicationUserSettings\":null,\"userSettings\":{\"user_id\":null,\"activity_likes_enabled\":true,\"dashboard_nav_refresh_enabled\":false,\"is_guest_post_enabled\":true,\"invite_friends_nux_dismissed_at\":null,\"suggestions_feed_item_last_shown_at\":null,\"last_notification_alert_shown_at\":null,\"disable_reply_hiding\":false,\"newest_seen_chat_item_published_at\":null,\"explicitContentEnabled\":false,\"contactMatchingEnabled\":false,\"messageRequestLevel\":\"everyone\",\"liveStreamAcceptableInviteLevel\":\"everyone\",\"liveStreamAcceptableChatLevel\":\"everyone\",\"creditTokensTreatmentExposed\":false,\"appBadgeIncludesChat\":false,\"autoPlayVideo\":true,\"autoAdvanceVideo\":true,\"smart_delivery_enabled\":false,\"chatbotTermsLastAcceptedAt\":null,\"has_seen_notes_post_app_upsell\":false,\"first_note_id\":null,\"show_concurrent_live_stream_viewers\":false,\"edit_profile_feed_item_dismissed_at\":null,\"mobile_permalink_app_upsell_seen_at\":null,\"new_user_checklist_enabled\":false,\"has_seen_youtube_shorts_auto_publish_announcement\":false,\"has_seen_publish_youtube_connect_upsell\":false,\"notificationQualityFilterEnabled\":true,\"hasSeenOnboardingNewslettersScreen\":false,\"bestsellerBadgeEnabled\":true,\"hasSelfIdentifiedAsCreator\":false,\"autoTranslateEnabled\":true,\"autoTranslateBlocklist\":[],\"fineTuneFeedItemSeenAt\":null,\"fineTuneFeedItemDismissedAt\":null,\"aiGeneratedTextMode\":\"show\",\"feedVideoPreference\":5,\"feedAudioPreference\":5,\"feedLongerPostsPreference\":5,\"feedChatPreference\":5},\"mux_env_key\":\"u42pci814i6011qg3segrcpp9\",\"persona_environment_id\":\"env_o1Lbk4JhpY4PmvNkwaBdYwe5Fzkt\",\"sentry_environment\":\"production\",\"launchWelcomePage\":false,\"pendingInviteForActiveLiveStream\":null,\"isEligibleForLiveStreamCreation\":true,\"webviewPlatform\":null,\"noIndex\":false,\"post\":{\"audience\":\"everyone\",\"audience_before_archived\":null,\"canonical_url\":\"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous\",\"default_comment_sort\":null,\"editor_v2\":false,\"exempt_from_archive_paywall\":false,\"free_unlock_required\":false,\"id\":148798453,\"podcast_art_url\":null,\"podcast_duration\":null,\"podcast_preview_upload_id\":null,\"podcast_upload_id\":null,\"podcast_url\":null,\"post_date\":\"2024-09-13T04:37:19.200Z\",\"updated_at\":\"2024-09-26T20:07:15.277Z\",\"publication_id\":1002265,\"search_engine_description\":\"This article defines Heterogeneous and Homogeneous SLIs with examples, illustrations and their pros and cons. It then concludes with a lightweight guide on when to use which one.\",\"search_engine_title\":null,\"section_id\":67723,\"should_send_free_preview\":false,\"show_guest_bios\":true,\"slug\":\"sli-heterogeneous-vs-homogeneous\",\"social_title\":null,\"subtitle\":\"Cons and pros of each approach and when to use which\",\"teaser_post_eligible\":true,\"title\":\"Heterogeneous SLI vs Homogeneous SLI\",\"type\":\"newsletter\",\"video_upload_id\":null,\"write_comment_permissions\":\"everyone\",\"meter_type\":\"none\",\"live_stream_id\":null,\"is_published\":true,\"restacks\":3,\"reactions\":{\"\u2764\":7},\"top_exclusions\":[],\"pins\":[],\"section_pins\":[],\"has_shareable_clips\":false,\"previous_post_slug\":\"sls\",\"next_post_slug\":\"slo-elastic-datadog-grafana\",\"cover_image\":\"https://substackcdn.com/image/fetch/$s_!aFXH!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png\",\"cover_image_is_square\":false,\"cover_image_is_explicit\":false,\"videoUpload\":null,\"podcastFields\":{\"post_id\":148798453,\"podcast_episode_number\":null,\"podcast_season_number\":null,\"podcast_episode_type\":null,\"should_syndicate_to_other_feed\":null,\"syndicate_to_section_id\":null,\"hide_from_feed\":false,\"free_podcast_url\":null,\"free_podcast_duration\":null,\"preview_contains_ad\":false,\"was_imported_self_serve_sync\":false,\"draft_free_podcast_url\":null,\"draft_free_podcast_duration\":null},\"podcastUpload\":null,\"podcastPreviewUpload\":null,\"voiceover_upload_id\":null,\"voiceoverUpload\":null,\"has_voiceover\":false,\"description\":\"Cons and pros of each approach and when to use which\",\"body_html\":\"<p>At the heart of the <a href=\\\"https://blog.alexewerlof.com/p/sli\\\">Service Levels</a> is the ratio between <a href=\\\"https://blog.alexewerlof.com/p/sli-good\\\">good</a> and <a href=\\\"https://blog.alexewerlof.com/p/valid-vs-total\\\">valid</a>:</p><ul><li><p>Percentage of <code>requests</code> where <code>response.latency &lt; 300ms</code></p></li><li><p>Percentage of <code>uptime probes</code> where <code>response.code == 200</code></p></li><li><p>Percentage of <code>database records</code> where <code>fields.*.age &lt; 365 days</code></p></li><li><p>Percentage of <code>authenticated API requests</code> where <code>http_response.code &lt; 500</code></p></li></ul><p>When it comes to implement and calculate those percentages, there are two approaches:</p><ul><li><p><strong>Heterogeneous:</strong> good and valid are two different metrics with an assumed correlation.</p></li><li><p><strong>Homogeneous:</strong> good and valid come from processing the same metric where good and valid are tightly coupled</p></li></ul><p>This article introduces both types with examples and illustrations ending with a recommendation.</p><h2>Heterogeneous</h2><p>This type of SLI queries two different metrics to count the number of:</p><p>Good and valid:</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLI = \\\\\\\\frac{\\\\\\\\text{good}}{\\\\\\\\text{valid}} \\\\\\\\times 100&quot;,&quot;id&quot;:&quot;SBKHVFIBZQ&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>or good and bad:</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLI = \\\\\\\\frac{\\\\\\\\text{good}}{\\\\\\\\text{good} + \\\\\\\\text{bad}} \\\\\\\\times 100\\\\n&quot;,&quot;id&quot;:&quot;DODRDTNUOR&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>or bad and valid:</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLI = \\\\\\\\frac{\\\\\\\\text{valid} - \\\\\\\\text{bad}}{\\\\\\\\text{valid}} \\\\\\\\times 100\\\\n&quot;,&quot;id&quot;:&quot;RXYEGBPOCJ&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>Regardless of the approach, it ends up querying two metrics.</p><p>Example: Availability of online purchase flow:</p><ul><li><p>Valid: number of unique sessions where the user clicked on the \u201CPay\u201D button on the check out page</p></li><li><p>Bad: number of payments failing due to payment gateway issues</p></li><li><p>Good = Valid - Bad</p></li></ul><p><em>Note: we deliberately filter out other failures like: when the user doesn\u2019t have enough money, or entered the wrong payment information because <a href=\\\"https://blog.alexewerlof.com/p/responsible-for-control\\\">you should never be responsible for what you don't control</a>.</em></p><p>On the surface, it looks reasonable, but in practice there are multiple nuances. The biggest issue is the assumed correlation between the datapoints of two different metrics over time:</p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!aFXH!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!aFXH!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 424w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 848w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1272w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png\\\" width=\\\"1017\\\" height=\\\"720\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:720,&quot;width&quot;:1017,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:53530,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!aFXH!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 424w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 848w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1272w, https://substackcdn.com/image/fetch/$s_!aFXH!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F9885c5ab-8dc7-4964-b7a6-8095c4c5901e_1017x720.png 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a><figcaption class=\\\"image-caption\\\">In this lookback window, there are 6 good events and 8 valid events but they are not corelated</figcaption></figure></div><p>This is because the data points of two separate metrics don\u2019t exactly match. As a result, for any type of lookback window (e.g. SLS or Alerting), we may end up with an inaccurate measurement.</p><p>The problem doesn\u2019t stop at the timestamp level. It is practically impossible to guarantee a 1-1 mapping between valid events and good events when they\u2019re measuring different things, at different locations, and different times.</p><p>Another obvious issue is the fact that we need to measure, store, and query two separate metrics (<code>valid</code> and either <code>good</code> or <code>bad</code>).</p><h3>Pros</h3><ul><li><p>Can correlate events across different systems which may map better to how the consumers perceives reliability of the service</p></li><li><p>Easier to reason about for beginners</p></li><li><p>Easier to implement by conventional Observability providers (in the next articles we\u2019ll review how Elastic, Datadog, and Grafana implement service levels)</p></li></ul><p class=\\\"button-wrapper\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe now&quot;,&quot;action&quot;:null,&quot;class&quot;:null}\\\" data-component-name=\\\"ButtonCreateButton\\\"><a class=\\\"button primary\\\" href=\\\"https://blog.alexewerlof.com/subscribe?\\\"><span>Subscribe now</span></a></p><h3>Cons</h3><ul><li><p>It might be harder to work with two datasets due to broken correlation between datapoints.</p></li><li><p>Less efficient due to requiring 2 metrics</p></li></ul><h2>Homogeneous</h2><p>Homogeneous SLIs come directly from the fact that the SLI formula is a percentage:</p><div class=\\\"latex-rendered\\\" data-attrs=\\\"{&quot;persistentExpression&quot;:&quot;SLI = \\\\\\\\frac{\\\\\\\\text{good}}{\\\\\\\\text{valid}} \\\\\\\\times 100&quot;,&quot;id&quot;:&quot;OOATSIMYSW&quot;}\\\" data-component-name=\\\"LatexBlockToDOM\\\"></div><p>All you have to do is to:</p><ol><li><p>Filter the metric to only contain valid data points</p></li><li><p>Go through the data points and count the number of good (or bad) events</p></li><li><p>Divide it by the total number of data points</p></li></ol><p>It\u2019s easier to show it with a diagram:</p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!6B2-!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!6B2-!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 424w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 848w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1272w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png\\\" width=\\\"1015\\\" height=\\\"676\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/db6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:676,&quot;width&quot;:1015,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:52288,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!6B2-!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 424w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 848w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1272w, https://substackcdn.com/image/fetch/$s_!6B2-!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fdb6be925-84d6-43ad-a656-f24d62d9636e_1015x676.png 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a><figcaption class=\\\"image-caption\\\">In this lookback window, 6 out of 8 events are good</figcaption></figure></div><p>The biggest advantage of this method is the reliable correlation between good, bad and valid.</p><p><em>Note: an upcoming feature of <a href=\\\"https://slc.alexewerlof.com/\\\">SLC</a>, introduces a simulator. It uses an O(1) algorithm to process the metric data in one pass. I\u2019ll write more about that technique once the feature is out.</em></p><div class=\\\"subscription-widget-wrap-editor\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}\\\" data-component-name=\\\"SubscribeWidgetToDOM\\\"><div class=\\\"subscription-widget show-subscribe\\\"><div class=\\\"preamble\\\"><p class=\\\"cta-caption\\\">If you want to stay in the know for SLC development and learn more along the way, you can subscribe for free.</p></div><form class=\\\"subscription-widget-subscribe\\\"><input type=\\\"email\\\" class=\\\"email-input\\\" name=\\\"email\\\" placeholder=\\\"Type your email\u2026\\\" tabindex=\\\"-1\\\"><input type=\\\"submit\\\" class=\\\"button primary\\\" value=\\\"Subscribe\\\"><div class=\\\"fake-input-wrapper\\\"><div class=\\\"fake-input\\\"></div><div class=\\\"fake-button\\\"></div></div></form></div></div><p>An obvious advantage of a homogeneous SLI is that it only needs to measure, store, and query one metric.</p><p>The downside is that your SLI may not readily be one metric. You may need to use a data processing pipeline that takes in 2 metrics in and spits out a clean homogeneous SLI. This can introduce a delay and cost to your setup.</p><div class=\\\"captioned-image-container\\\"><figure><a class=\\\"image-link image2 is-viewable-img\\\" target=\\\"_blank\\\" href=\\\"https://substackcdn.com/image/fetch/$s_!CzlQ!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png\\\" data-component-name=\\\"Image2ToDOM\\\"><div class=\\\"image2-inset\\\"><picture><source type=\\\"image/webp\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!CzlQ!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 424w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 848w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1272w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1456w\\\" sizes=\\\"100vw\\\"><img src=\\\"https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png\\\" width=\\\"1028\\\" height=\\\"367\\\" data-attrs=\\\"{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:367,&quot;width&quot;:1028,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:37047,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:true,&quot;topImage&quot;:false,&quot;internalRedirect&quot;:null,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}\\\" class=\\\"sizing-normal\\\" alt=\\\"\\\" srcset=\\\"https://substackcdn.com/image/fetch/$s_!CzlQ!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 424w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 848w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1272w, https://substackcdn.com/image/fetch/$s_!CzlQ!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2F8cae679c-2460-4724-ac03-7a1eabc78dd3_1028x367.png 1456w\\\" sizes=\\\"100vw\\\" loading=\\\"lazy\\\"></picture><div class=\\\"image-link-expand\\\"><div class=\\\"pencraft pc-display-flex pc-gap-8 pc-reset\\\"><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container restack-image\\\"><svg aria-hidden=\\\"true\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 20 20\\\" fill=\\\"none\\\" stroke-width=\\\"1.5\\\" stroke=\\\"var(--color-fg-primary)\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" xmlns=\\\"http://www.w3.org/2000/svg\\\"><g><path d=\\\"M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882\\\"></path></g></svg></button><button tabindex=\\\"0\\\" type=\\\"button\\\" class=\\\"pencraft pc-reset pencraft icon-container view-image\\\"><svg xmlns=\\\"http://www.w3.org/2000/svg\\\" width=\\\"20\\\" height=\\\"20\\\" viewBox=\\\"0 0 24 24\\\" fill=\\\"none\\\" stroke=\\\"currentColor\\\" stroke-width=\\\"2\\\" stroke-linecap=\\\"round\\\" stroke-linejoin=\\\"round\\\" class=\\\"lucide lucide-maximize2 lucide-maximize-2\\\"><polyline points=\\\"15 3 21 3 21 9\\\"></polyline><polyline points=\\\"9 21 3 21 3 15\\\"></polyline><line x1=\\\"21\\\" x2=\\\"14\\\" y1=\\\"3\\\" y2=\\\"10\\\"></line><line x1=\\\"3\\\" x2=\\\"10\\\" y1=\\\"21\\\" y2=\\\"14\\\"></line></svg></button></div></div></div></a></figure></div><p>The good news is that most metrics don\u2019t need this type of processing. For example:</p><ul><li><p><code>Uptime calculation:</code> divide the percentage of successful probes during the window, multiply by 100</p></li><li><p><code>Percentage of authenticated requests where latency &lt; 200ms</code>: find all the authenticated requests in the window, filter out any events where latency \u2265 200 and divide this count to the total number of requests x 100</p></li></ul><h3>Pros</h3><ul><li><p>It is more intuitive because it\u2019s closer to how normalized SLI is literally defined</p></li><li><p>It requires half as many metrics (only <code>valid</code>)</p></li><li><p>The SLS calculations essentially turns into a percentile calculation so it is easier to reason about the dataset</p></li></ul><h3>Cons</h3><ul><li><p>When the good and valid come from different systems, it requires extra processing to corelate the events which adds to the cost and complexity</p></li><li><p>None of the observability providers that I have investigated (Datadog, Elastic, Grafana) support homogeneous metrics out of the box.</p></li></ul><h1>When to use which?</h1><p>Whether you use homogeneous or heterogeneous metrics depends on how the consumers perceive reliability, your tooling, and budget (time, and money).</p><p>Homogeneous metrics are easier to reason about and often come naturally out of the box.</p><p>If you can ensure a tight coupling between the two metrics, a heterogenous metric can work too.</p><div><hr></div><p><em>These posts take anywhere from a few hours to a few days to ideate, draft, research, illustrate, edit, and publish. I pull these hours from my private time, vacation days and weekends.</em></p><p><em>Recently I went down in working hours and salary by 10% to be able to spend more time learning and sharing my experience with the public.</em></p><p><em><a href=\\\"https://blog.alexewerlof.com/p/faq#%C2%A7payment\\\">My monetization strategy</a>&nbsp;is to give away most content for free because I believe information should be free and accessible. You can support this cause by sparing a few bucks for a paid subscription. As a token of appreciation, you get access to the Pro-Tips sections (on some articles) as well as my online book&nbsp;<a href=\\\"https://blog.alexewerlof.com/p/rem\\\">Reliability Engineering Mindset</a>. Right now, you can get 20% off via&nbsp;<a href=\\\"https://blog.alexewerlof.com/protipsdiscount\\\">this link</a>. You can also <a href=\\\"https://blog.alexewerlof.com/leaderboard\\\">invite your friends</a> to gain free access or get a discounted group subscription. There\u2019s also a <a href=\\\"https://blog.alexewerlof.com/leaderboard\\\">referral bonus program to gain free subscriptions</a>.</em></p><p><em>Thanks in advance for helping these words reach further and impact the software engineering community.</em></p><div class=\\\"captioned-button-wrap\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&utm_medium=email&utm_content=share&action=share&quot;,&quot;text&quot;:&quot;Share&quot;}\\\" data-component-name=\\\"CaptionedButtonToDOM\\\"><div class=\\\"preamble\\\"><p class=\\\"cta-caption\\\">If you find this post insightful, please share it in your circles to inspire others.</p></div><p class=\\\"button-wrapper\\\" data-attrs=\\\"{&quot;url&quot;:&quot;https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&utm_medium=email&utm_content=share&action=share&quot;,&quot;text&quot;:&quot;Share&quot;}\\\" data-component-name=\\\"ButtonCreateButton\\\"><a class=\\\"button primary\\\" href=\\\"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous?utm_source=substack&utm_medium=email&utm_content=share&action=share\\\"><span>Share</span></a></p></div>\",\"has_dynamic_content\":false,\"truncated_body_text\":\"At the heart of the Service Levels is the ratio between good and valid:\",\"wordcount\":978,\"post_preview_limit\":null,\"language\":\"en\",\"postTags\":[{\"id\":\"5e680a13-60a3-45b8-b0a0-6275b3f1ff23\",\"publication_id\":1002265,\"name\":\"measurement\",\"slug\":\"measurement\",\"hidden\":false},{\"id\":\"ae2bf941-bf61-45c2-a8b9-a6dc27247c3a\",\"publication_id\":1002265,\"name\":\"service levels\",\"slug\":\"service-levels\",\"hidden\":false}],\"postCountryBlocks\":[],\"headlineTest\":null,\"coverImagePalette\":{\"Vibrant\":{\"rgb\":[28,196,84],\"population\":4},\"DarkVibrant\":{\"rgb\":[17,108,64],\"population\":41},\"LightVibrant\":{\"rgb\":[244,237,223],\"population\":76},\"Muted\":{\"rgb\":[164,82,82],\"population\":4},\"DarkMuted\":{\"rgb\":[88,48,64],\"population\":2},\"LightMuted\":{\"rgb\":[214,209,196],\"population\":3}},\"publishedBylines\":[{\"id\":87732486,\"name\":\"Alex Ewerl\u00F6f\",\"handle\":\"alexewerlof\",\"photo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"bio\":\"Writes about technical leadership, growth mindset, and system reliability engineering. Senior Staff Engineer, MSc Systems Engineering from KTH, Stockholmer, dad, amateur artist. Read more here: https://www.alexewerlof.com/who\",\"profile_set_up_at\":\"2022-07-14T22:27:32.130Z\",\"reader_installed_at\":\"2022-10-11T17:24:45.190Z\",\"publicationUsers\":[{\"id\":947579,\"user_id\":87732486,\"publication_id\":1002265,\"role\":\"admin\",\"public\":true,\"is_primary\":true,\"publication\":{\"id\":1002265,\"name\":\"Alex Ewerl\u00F6f Notes\",\"subdomain\":\"alexewerlof\",\"custom_domain\":\"blog.alexewerlof.com\",\"custom_domain_optional\":false,\"hero_text\":\"Technical Leadership, Reliability Engineering, Growth\",\"logo_url\":\"https://substack-post-media.s3.amazonaws.com/public/images/8c58cb07-9341-402b-bcdb-9fa767c2cdac_500x500.png\",\"author_id\":87732486,\"primary_user_id\":87732486,\"theme_var_background_pop\":\"#786CFF\",\"created_at\":\"2022-07-14T22:27:58.683Z\",\"email_from_name\":\"Alex Ewerl\u00F6f Notes\",\"copyright\":\"Alex Ewerl\u00F6f\",\"founding_plan_name\":\"VIP supporter\",\"community_enabled\":true,\"invite_only\":false,\"payments_state\":\"enabled\",\"language\":null,\"explicit\":false,\"homepage_type\":\"newspaper\",\"is_personal_mode\":false,\"logo_url_wide\":\"https://substack-post-media.s3.amazonaws.com/public/images/bd56dc7c-4b9f-43f2-99a1-ecc995284940_1200x256.png\"}},{\"id\":8561877,\"user_id\":87732486,\"publication_id\":8361889,\"role\":\"admin\",\"public\":true,\"is_primary\":false,\"publication\":{\"id\":8361889,\"name\":\"AI Reliability Engineering\",\"subdomain\":\"aireliabilityengineering\",\"custom_domain\":null,\"custom_domain_optional\":false,\"hero_text\":\"From the Author of Reliability Engineering Mindset but focused on AI systems and components.\",\"logo_url\":\"https://substackcdn.com/image/fetch/f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fbucketeer-e05bbc84-baa3-437e-9518-adb32be77984.s3.amazonaws.com%2Fpublic%2Fimages%2Fe2713990-da82-481b-b579-01a7aaa5b85b_560x560.jpeg\",\"author_id\":87732486,\"primary_user_id\":null,\"theme_var_background_pop\":\"#FF6719\",\"created_at\":\"2026-03-18T10:58:12.396Z\",\"email_from_name\":null,\"copyright\":\"Alex Ewerl\u00F6f\",\"founding_plan_name\":null,\"community_enabled\":true,\"invite_only\":false,\"payments_state\":\"disabled\",\"language\":null,\"explicit\":false,\"homepage_type\":\"newspaper\",\"is_personal_mode\":false,\"logo_url_wide\":null}}],\"twitter_screen_name\":\"alexewerlof\",\"is_guest\":false,\"bestseller_tier\":null,\"status\":{\"bestsellerTier\":null,\"subscriberTier\":null,\"leaderboard\":null,\"vip\":false,\"badge\":null,\"subscriber\":null}}],\"reaction\":null,\"reaction_count\":7,\"comment_count\":0,\"child_comment_count\":0,\"audio_items\":[{\"post_id\":148798453,\"voice_id\":\"en-US-ChristopherMultilingualNeural\",\"audio_url\":\"https://substack-video.s3.amazonaws.com/video_upload/post/148798453/tts/c1d72708-bcfc-4566-9107-c207bcb0efaa/en-US-ChristopherMultilingualNeural.mp3\",\"type\":\"tts\",\"status\":\"completed\"}],\"is_geoblocked\":false,\"hasCashtag\":false,\"section\":{\"id\":67723,\"created_at\":\"2023-05-31T19:57:24.859Z\",\"updated_at\":\"2024-03-22T13:16:12.203Z\",\"publication_id\":1002265,\"name\":\"Reliability Engineering\",\"description\":\"Concepts that help you with building reliable systems and architecture\",\"slug\":\"sre\",\"is_podcast\":false,\"is_live\":true,\"is_default_on\":true,\"sibling_rank\":1,\"port_status\":\"success\",\"logo_url\":null,\"hide_from_navbar\":false,\"email_from_name\":\"\",\"hide_posts_from_pub_listings\":false,\"email_banner_url\":null,\"cover_photo_url\":null,\"hide_intro_title\":false,\"hide_intro_subtitle\":false,\"ignore_publication_email_settings\":false,\"custom_config\":{},\"unifiedPodcastSettings\":null,\"podcastSettings\":null,\"showLinks\":[],\"pageTheme\":{\"id\":51609,\"publication_id\":1002265,\"section_id\":67723,\"page\":null,\"page_hero\":\"default\",\"page_posts\":\"grid\",\"show_podcast_links\":true,\"hero_alignment\":\"center\"},\"podcastPalette\":{\"DarkMuted\":{\"population\":72,\"rgb\":[73,153,137]},\"DarkVibrant\":{\"population\":6013,\"rgb\":[4,100,84]},\"LightMuted\":{\"population\":7,\"rgb\":[142,198,186]},\"LightVibrant\":{\"population\":3,\"rgb\":[166,214,206]},\"Muted\":{\"population\":6,\"rgb\":[92,164,156]},\"Vibrant\":{\"population\":5,\"rgb\":[76,164,146]}},\"spotify_podcast_settings\":null,\"unified_podcast_settings\":null}},\"comments\":[],\"canonicalUrl\":\"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous\",\"inlineComments\":false,\"readerIsSearchCrawler\":false,\"ogUrl\":\"https://blog.alexewerlof.com/p/sli-heterogeneous-vs-homogeneous\",\"bannedFromNotes\":false,\"themeVariables\":{\"color_theme_bg_pop\":\"#FFBC52\",\"background_pop\":\"#FFBC52\",\"color_theme_bg_web\":\"#001426\",\"cover_bg_color\":\"#001426\",\"cover_bg_color_secondary\":\"#0f2233\",\"background_pop_darken\":\"#ffb238\",\"print_on_pop\":\"#ffffff\",\"color_theme_bg_pop_darken\":\"#ffb238\",\"color_theme_print_on_pop\":\"#ffffff\",\"color_theme_bg_pop_20\":\"rgba(255, 188, 82, 0.2)\",\"color_theme_bg_pop_30\":\"rgba(255, 188, 82, 0.3)\",\"print_pop\":\"#ffbc52\",\"color_theme_accent\":\"#ffbc52\",\"cover_print_primary\":\"#ffffff\",\"cover_print_secondary\":\"#d9d9d9\",\"cover_print_tertiary\":\"#d9d9d9\",\"cover_border_color\":\"#ffffff\",\"font_family_headings_preset\":\"'SF Pro Display', -apple-system, system-ui, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'\",\"font_weight_headings_preset\":900,\"font_family_body_preset\":\"Merriweather,sans-serif\",\"font_weight_body_preset\":400,\"font_preset_heading\":\"sans\",\"font_preset_body\":\"fancy_serif\",\"home_hero\":\"feature-media\",\"home_posts\":\"custom\",\"home_show_top_posts\":true,\"web_bg_color\":\"#001426\",\"background_contrast_1\":\"#0f2233\",\"background_contrast_2\":\"#223443\",\"background_contrast_3\":\"#485663\",\"background_contrast_4\":\"#6d7882\",\"background_contrast_5\":\"#aeb5ba\",\"color_theme_bg_contrast_1\":\"#0f2233\",\"color_theme_bg_contrast_2\":\"#223443\",\"color_theme_bg_contrast_3\":\"#485663\",\"color_theme_bg_contrast_4\":\"#6d7882\",\"color_theme_bg_contrast_5\":\"#aeb5ba\",\"color_theme_bg_elevated\":\"#0f2233\",\"color_theme_bg_elevated_secondary\":\"#223443\",\"color_theme_bg_elevated_tertiary\":\"#485663\",\"color_theme_detail\":\"#192b3c\",\"background_contrast_pop\":\"rgba(255, 188, 82, 0.4)\",\"color_theme_bg_contrast_pop\":\"rgba(255, 188, 82, 0.4)\",\"theme_bg_is_dark\":\"1\",\"print_on_web_bg_color\":\"hsl(208.4210526315789, 25.00000000000006%, 90.74509803921569%)\",\"print_secondary_on_web_bg_color\":\"#99a1a8\",\"footer_bg_color\":\"#000C17\",\"footer_bg_color_h\":\"208.69565217391306\",\"footer_bg_color_s\":\"100%\",\"footer_bg_color_l\":\"4.509803921568627%\",\"print_on_footer_bg_color\":\"hsl(208.69565217391306, 25.000000000000057%, 90.45098039215686%)\",\"print_secondary_on_footer_bg_color\":\"#999ea2\",\"footer_bg_contrast_1\":\"#0f1b25\",\"footer_bg_contrast_2\":\"#222d36\",\"footer_bg_contrast_3\":\"#485158\",\"footer_bg_contrast_4\":\"#6d737a\",\"footer_bg_elevated\":\"#0f1b25\",\"footer_bg_elevated_secondary\":\"#222d36\",\"footer_bg_elevated_tertiary\":\"#485158\",\"footer_detail_color\":\"#19242e\",\"background_pop_rgb\":\"255, 188, 82\",\"color_theme_bg_pop_rgb\":\"255, 188, 82\",\"color_theme_accent_rgb\":\"255, 188, 82\"},\"recentEpisodes\":null,\"trackFrontendVisit\":true,\"activeLiveStream\":null,\"freeTrialCoupon\":{\"id\":\"3cce95ff\",\"trial_period_days\":7},\"defaultCoupon\":null,\"isChatActive\":false,\"publicationPageAlert\":null,\"features\":{},\"browser\":{\"name\":\"Chrome\",\"version\":\"125.0\",\"major\":\"125\"},\"showCookieBanner\":false,\"disabledCookies\":[],\"dd_env\":\"prod\",\"dd_ti\":true}")</script>
<script nonce="ojec8Slr706y9DeQ9hU8iA">window._analyticsConfig = JSON.parse("{\"properties\":{\"subdomain\":\"alexewerlof\",\"publication_id\":1002265,\"has_plans\":true,\"pub_community_enabled\":true,\"is_personal_publication\":false,\"section_name\":\"Reliability Engineering\",\"section_slug\":\"sre\",\"section_id\":67723,\"section_is_podcast\":false,\"is_subscribed\":false,\"is_free_subscribed\":false,\"is_author\":false,\"is_contributor\":false,\"is_admin\":false,\"is_founding\":false},\"adwordsAccountId\":\"AW-316245675\",\"adwordsEventSendTo\":\"Tf76CKqcyL4DEKuN5pYB\"}")</script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/lib-router.7371871e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/55188.571db0c6.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/62357.a0731d37.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53754.d196682b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/33485.2686bb5d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/2237.ae8857e4.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/37707.4614ce58.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/9351.41564edd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/80821.b2140fcd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/44292.f3dc2b43.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/70291.7aa24e85.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/17499.1820773d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/57975.765aca5a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/19714.2f1bdde5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48320.4e726ad5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93000.f03f24de.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/44014.f579d62b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/43745.80c75c78.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/60892.92b9fc9c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/40646.258e49f2.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/87906.d493457b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/36479.ce61e623.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/17706.015b0f71.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93977.f1207089.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/37606.b91ab2ef.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/94311.b93f6845.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/89356.66161d1e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/21262.211a7337.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/47925.24a01d36.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/80220.03bd4c41.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/71505.3dc43e33.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/11100.5d148f2c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/3663.86d95e8c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/18725.a5a682c3.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/86118.ff1ec843.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/93519.7fe128ac.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/84828.c78aabc1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/5075.d6e9f8ec.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/29231.a7af5911.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/56725.2b32bbb6.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/42336.f1c17ded.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/89879.1d0af2b9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/70793.951c11cb.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/39522.58e078b0.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53164.dfde36c8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/74584.94c6b3f1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/71199.a327e9f4.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/63266.8bb0d59c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/47358.8f5c5991.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/4492.cb326b80.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/88089.680833b5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/97348.df6a856d.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/52109.cf3bcc2c.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/56256.8a1bc5dd.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/77410.3f20fb36.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/25058.bdbc4e21.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/58483.3adddb8a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/94881.0a97506f.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/27386.09a9082f.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/10174.7f0face7.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/92610.a4fc1daf.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91214.cb10b4b8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/11244.b723f409.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/99260.28b0ed6a.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48445.7d5c5ba3.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/76768.9a2f2bae.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/41932.6c688f22.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/12114.979fb38e.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/48409.9732c6f9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/26252.4f5ae3be.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/53871.2923c5c9.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/18494.588a06d1.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/99068.bd2e1fba.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91850.79d3f415.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/49047.c7f428fb.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/16075.098bcbcf.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/28856.2eb51db5.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/95396.72d1d844.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/63175.bbf1c283.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/74628.2e8ed950.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/32552.889dd584.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/27313.c287f2d8.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/mainReactRouter.6c265246.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/91507.9b9761ae.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/54770.b40bf629.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/30054.07cd629b.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/78118.35b48b09.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/57051.f37fb930.js" charset="utf-8"></script>
<script defer type="module" src="https://substackcdn.com/bundle/static/js/78191.24075434.js" charset="utf-8"></script>
<script nonce="ojec8Slr706y9DeQ9hU8iA" nomodule>
(function() {
var message = 'Your browser does not support modern JavaScript modules. Please upgrade your browser for the best experience.';
var warningDiv = document.createElement('div');
warningDiv.style.color = 'red';
warningDiv.style.padding = '10px';
warningDiv.style.margin = '10px 0';
warningDiv.style.border = '1px solid red';
warningDiv.style.backgroundColor = 'lightyellow';
warningDiv.innerText = message;
document.body.prepend(warningDiv);
})();
</script>
<!-- Datadog Analytics -->
<script nonce="ojec8Slr706y9DeQ9hU8iA">
(function(h,o,u,n,d) {
h=h[d]=h[d]||{q:[],onReady:function(c){h.q.push(c)}}
d=o.createElement(u);d.async=1;d.src=n
n=o.getElementsByTagName(u)[0];n.parentNode.insertBefore(d,n)
})(window,document,'script','https://www.datadoghq-browser-agent.com/us1/v5/datadog-rum.js','DD_RUM')
window.DD_RUM.onReady(function() {
window.DD_RUM.init({
clientToken: 'puba71073f072643721169b68f352438710',
applicationId: '2e321b35-c76b-4073-8d04-cc9a10461793',
site: 'datadoghq.com',
service: 'web',
env: window._preloads.dd_env,
version: '8b4c00716b2bc0f7ca1fded553014f7e37b5b07a',
sessionSampleRate: 1,
sessionReplaySampleRate: 10,
trackUserInteractions: window._preloads.dd_ti,
trackResources: true,
trackLongTasks: true,
defaultPrivacyLevel: 'mask-user-input',
allowedTracingUrls: [/https?:\/\/(.+\/.)?substack(cdn)?\.com/]
});
})
</script>
<!-- End Datadog Analytics -->
<!-- Cloudflare Web Analytics -->
<script defer src="https://static.cloudflareinsights.com/beacon.min.js" data-cf-beacon='{"token": "216309cffb464db4b0e02daf0b8e8060"}'></script>
<!-- End Cloudflare Web Analytics -->
<!-- Fallback tracking pixels -->
<noscript>
<style>
#nojs-banner {
position: fixed;
bottom: 0;
left: 0;
padding: 16px 16px 16px 32px;
width: 100%;
box-sizing: border-box;
background: red;
color: white;
font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
font-size: 13px;
line-height: 13px;
}
#nojs-banner a {
color: inherit;
text-decoration: underline;
}
</style>
<div id="nojs-banner">
This site requires JavaScript to run correctly. Please <a href="https://enable-javascript.com/" target="_blank">turn on JavaScript</a> or unblock scripts
</div>
</noscript>
<script type="module" src="https://static.cloudflareinsights.com/beacon.min.js/v31edd6df95cf4e85bb4c19e7a9bdbcba1788362987495" integrity="sha512-iIg7k2xntmwu6/uSb5tpc/hySgZc4eoL31yB29W6tJFo2akwjPWcEqnCEdJvGexCL0KEQwVYv5BlowfhVz26hg==" nonce="ojec8Slr706y9DeQ9hU8iA" data-cf-beacon='{"version":"2024.11.0","token":"68cfe66b5c4749e2ba64d4d9640c04c0","spa":2}' crossorigin="anonymous"></script>
</body>
</html>