Disaster recovery (DR)
Disaster recovery (DR) is the set of plans, tools and practices for restoring systems and data after a major failure. Examples are losing a cloud region, a ransomware attack or a bad migration that corrupts data. DR is judged by two targets set in RTO and RPO: how fast you must be back and how much data you may lose.
How it works
Teams pick a strategy that matches their targets and budget. Common options, from cheapest to fastest:
Backup and restore: RTO in hours.
Pilot light: core data replicated, compute started on demand.
Warm standby: a scaled-down copy running in another region.
Multi-site active-active: near-zero RTO, highest cost.
For example, hourly backups give an RPO of up to 1 hour. Restoring 2 TB at 500 MB per second takes about 67 minutes before any checks, so a 30 minute RTO needs a standby, not backups alone.
Why it matters in production
High availability handles a failed node; DR handles losing the whole site or the data itself. A DR plan nobody has rehearsed is a guess. Regular restore tests and failover drills are what make RTO and RPO real.
See also
On the One2N blog
Disaster recovery for SREs: the practical playbook for RTO, RPO, and cutover
Optimizing MongoDB backup strategy: lessons from achieving a 1-hour RPO
Further reading
