Comparison
Change failure ratevsMean time to restore
Change failure rate
one deploy in six needed a fix or a rollback, and nobody had counted until someone asked.
The proportion of deployments causing a degradation that requires remediation. It is the stability half of the DORA pair, and it exists to catch the obvious objection to shipping frequently. A low rate combined with low frequency usually means the team is not shipping rather than that it is careful, which is why the four numbers are only meaningful together.
Full entry →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 →