SLI
A Service Level Indicator — the specific metric used to measure whether an SLO is being met.
Definition
A Service Level Indicator (SLI) is a carefully selected metric that quantifies one aspect of the level of service being provided. SLIs are the measurements used to evaluate whether a Service Level Objective (SLO) is being met.
In depth
Common SLIs include request success rate (good requests / total requests), latency (percentage of requests below a threshold), availability (fraction of time the service is reachable), and error rate. A good SLI directly measures something meaningful to users, is cheap to compute continuously, and correlates closely with user experience. The SLI feeds the SLO: if the SLI target is 99.9% of requests completing in under 200ms over a 30-day window, that becomes the SLO. When the SLI falls below the SLO threshold, the error budget is consumed. obseria.io lets teams define custom SLIs from any metric, log query, or synthetic check and tracks them automatically against configured SLOs.
Related terms
See SLI in action
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