What is Service Level Indicator (SLI)?

Why does Service Level Indicator (SLI) matter?

Reliability discussions become actionable only when the observed behavior, eligible events, and measurement point are explicit.

Service Level Indicator (SLI) in practice

Define numerator, denominator, exclusions, data source, and aggregation window, then validate that the indicator tracks an outcome users actually experience.

What is the common confusion about Service Level Indicator (SLI)?

An SLI is the measurement. An SLO is the target applied to that measurement over a defined period.

Learn Service Level Indicator (SLI) in the course

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Related terms

• Service Level Objective (SLO)A target range or threshold for a service-level indicator over a stated population and measurement window.
• AvailabilityThe proportion of eligible service interactions or time windows in which users can obtain the defined acceptable service under a stated…
• Tail LatencyThe latency experienced by the slowest portion of requests, commonly summarized with a high percentile under a stated workload and time…
• ObservabilityThe ability to understand an AI system's behavior from recorded inputs, outputs, state transitions, tool calls, timings, costs, errors,…
• Error BudgetThe amount of unsuccessful service allowed by a service-level objective over its measurement window before the objective is exhausted.

Sources

• Google SRE: Service Level Objectives

More terms in Reliability & operations

• Admission Control
• Availability
• Canary Release
• Deadline Propagation
• Error Budget
• Graceful Degradation
• Incident Response
• Load Shedding
• Postmortem
• Readiness Probe
• Retry Budget
• Rollback
• Saturation
• Service Level Objective (SLO)
• Shadow Traffic
• Tail Latency

Open the Reliability & operations list in the glossary