Why it matters

Without SLOs, reliability discussions are subjective. With them, decisions are data-driven. Adopting the framework transforms ops maturity.

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The architecture

SLI: specific measurement. Availability = successful requests / total requests. Latency = p99 time.

SLO: target for the SLI. 99.9% availability. p99 latency < 300ms.

SLO frameworkSLImeasureSLOtargetError budget100% - SLOError budget spent on planned risk (deploys, experiments); depleted means slow down
SLI/SLO/budget cycle.
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How it works end to end

Error budget: amount of failure allowed. 99.9% SLO → 0.1% error budget = ~44 minutes/month.

Budget drives decisions: budget available → deploy risk. Budget depleted → freeze deploys, focus on reliability.

SLI selection: measure what users care about. Availability, latency, correctness, freshness.