Stage 1 · Lesson 1 of 6
Why 100 per cent is the wrong target
Site reliability engineering starts from an uncomfortable idea: a service should not be perfectly reliable. Users reach you through phones, Wi-Fi and networks that fail far more often than a well-run backend, so beyond a point they cannot notice extra reliability.
Each extra "" (99.9 to 99.99 per cent) costs roughly ten times more in redundancy, testing and slower releases. The right target is the level where users are happy and the business can still ship. This is what separates SRE from "keep everything up at any cost" operations, and it is the step up from the monitoring you met in the DevOps and cloud roadmap.
Common traptreating every outage as unacceptable, which pushes teams to freeze releases and hide instead of managing risk openly.
A question to check yourself, an AI practice session and 2 cheat sheet entries come with the full roadmap. Unlock
Resources for this stage
Start with· follow one of these
- BookFreeGoogle Site Reliability Engineering Book
Google · Advanced
Free online: read the chapters on embracing risk and service level objectives first
- BookFreeThe Site Reliability Workbook
Google (O'Reilly) · Intermediate
Free online: the Implementing SLOs chapter walks through a worked example and an error budget policy