Reliability

RTO / RPO

Recovery Time Objective is how long until service returns; Recovery Point Objective is how much data may be lost.

Why interviewers ask about it

Business decisions before engineering ones. And an untested backup is not a backup - quote the measured restore time.

Mean time between failures and mean time to recovery. Availability = MTBF / (MTBF + MTTR).

This term is part of the free System Design interview preparation module - browse the full glossary for every definition.