Chapter 1 of 6 · 4 practices · 3 min · 4-question quiz
Deciding what to measure
Start from what users experience. These practices turn that into a small set of indicators and objectives that every other signal supports.
Start: Define service level indicators as good events over valid events4 practices in this chapter
- 1Define service level indicators as good events over valid eventsA service level indicator (SLI) is a measurement of something users care about. The Google SRE workbook recommends expressing every SLI as a ratio: good events divided by valid events, so it always…
- 2Set SLOs below 100% and agree what happens when the budget runs outA service level objective (SLO) is a target for an SLI over a window, such as 99.9% of requests successful over 28 days. The gap to 100% is the error budget: the amount of failure you accept.
- 3Cover the four golden signals for every serviceThe SRE book's chapter on monitoring distributed systems says that if you can only measure four things about a user-facing system, measure these: These four give every dashboard the same first row…
- 4Measure latency with histograms and percentiles, not averagesAverages hide the slow requests users complain about. The SRE book gives the example of a service with a 100 ms mean latency where 1% of requests take several seconds.
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