RTO and RPO
RTO · RPO · Recovery Time Objective · Recovery Point Objective · maximum tolerable downtime · maximum tolerable data loss · DMIA · PDMA
The RTO is the maximum acceptable downtime for a service; the RPO is the maximum amount of data, expressed as time, that you are prepared to lose when restoring.
In practice
An RPO of 24 hours means a daily backup is enough, at the cost of losing a day’s work in the worst case; an RPO of 15 minutes calls for replication or very frequent backups. An RTO of 4 hours requires backups that restore quickly, standby infrastructure and a rehearsed procedure. These targets are set with the business, application by application, because the shorter they are, the more they cost. In French, they are also called DMIA (maximum tolerable downtime) and PDMA (maximum tolerable data loss).
Fictional case: an SME’s online shop has an RTO of 2 hours and an RPO of 5 minutes, its accounting system an RTO of 3 days and an RPO of 24 hours. The recovery budget goes mainly to the shop; accounting makes do with a well-tested nightly backup.
