Comparison
Mean time to restorevsRecovery time objective
Mean time to restore
the outage started at 09:14 and traffic was healthy again at 09:31, and that number is the one that got tracked.
How long it takes to restore service after a failure in production. It matters more than the failure rate for most systems, because failures are inevitable and duration is the part you can engineer: rollback speed, observability, a rehearsed on-call. Optimising for it changes design decisions, since a system that can be restored in minutes can accept risks that one requiring a four-hour restore cannot.
Full entry →Recovery time objective
the business says four hours, and the restore has never been timed, so nobody knows whether that is true.
The maximum acceptable time to restore service after a disaster: how long you may be down. It is a business decision that dictates architecture, because an hour and a day buy completely different designs. The only honest way to hold it is to measure a real restore, since an untimed objective is a number in a document rather than a property of the system.
Full entry →