AI Glossary
SLO (Service Level Objective)
Also known as: Service level objective
An SLO is a reliability target for a service, expressed as the percentage of good events over a time window — for example, 99.9% of responses under 2 seconds over 30 days.
SLI, SLO and SLA
- SLI: the measured indicator (e.g., share of successful responses).
- SLO: the internal target for that indicator.
- SLA: the contractual commitment, usually looser than the SLO.
Error budget
If your SLO is 99.9%, you can fail 0.1% of events. That’s the error budget: while it lasts, the team ships changes; when it runs out, reliability comes first.
SLOs for LLMs
Beyond availability and latency, LLM features need quality indicators (refusals, negative ratings) and cost per request.
Go deeper in the book
AI for SREs
Your LLM returned HTTP 200. And it was wrong. Learn to run AI with SRE discipline.