⚙️  SLOs (Service Level Objectives)

SLOs (Service Level Objectives)#

Internal targets for reliability that a service aims to meet.

Important

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What it is#

A Service Level Objective (SLO) is a measurable target for how a service should perform — usually a percentage or number. It is the goal for reliability, performance or availability that a team commits to.

The SLA, SLO, SLI hierarchy#

The three fit together. The SLA is the external contract with customers; the SLO is the internal target that supports it; and the SLI is the actual measurement used to check performance. The SLO sits in the middle — stricter than the SLA, expressed in terms the SLI can measure.

Examples and error budgets#

Typical SLOs cover availability (“99.9% uptime per month”, SLI = uptime %), latency (“95% of requests under 300 ms”), error rate (“under 0.1% of requests return 5xx in 30 days”) and throughput (“at least 5,000 requests per second at peak”). An SLO of 99.9% implies an error budget of 0.1% allowed downtime — the slack that decides when to prioritise reliability over new features, and that stops teams from the costly, unrealistic chase for 100%.

A worked example#

Suppose an SLA requires 99.5% uptime. The internal SLO is set at 99.9% for margin, and the SLI is measured uptime over the last 30 days. If uptime slips to 99.6%, the SLA is still safe but the SLO is breached — an early warning of reliability risk before any SLA penalty is triggered.


Theme: MLOps, Serving & Monitoring  ·  All terminology



See also

Source article Adapted (context, re-expressed) in our own words from: SLOs (Service Level Objectives) (insightful-data-lab.com).

Tags: purpose: reference topic: terminology level: advanced