Design a database disaster recovery strategy.

Comprehensive DR involves: RPO (Recovery Point Objective - max data loss) and RTO (Recovery Time Objective - max downtime). Components: continuous backups (WAL archiving, snapshots), replication (sync for zero data loss, async for performance), geographic distribution (multi-region replicas), automated failover (health checks, DNS/proxy switch), backup testing (regular restore drills). Tools: pg_basebackup, Barman, cloud snapshots. Consider: cost vs recovery guarantees, data sovereignty, network partitions, runbook documentation.