Fundamentals
SLI / SLO / SLA
An SLI is the measurement, an SLO is the internal target, an SLA is the contractual promise with penalties.
Why interviewers ask about it
The SLA must always be looser than the SLO. The error budget - the inverse of the SLO - turns arguments about risk into arithmetic.
Related terms
This term is part of the free System Design interview preparation module - browse the full glossary for every definition.