PostgreSQL 12 High Availability Cookbook - Third Edition

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There's one important corollary here. PostgreSQL replicas tend to immediately reflect every change made to the primary node. What happens if someone accidentally drops a table? In this case, the 3-2-1 rule by itself is not sufficient. Relying on replicas alone means we've permanently lost this data.

Thus, we strongly recommend the following additional rule: At least one copy must be a true backup.

Databases such as PostgreSQL are equipped with Point-In-Time-Recovery (PITR), which allows the user to start with any past backup and apply changes until it reaches a specific point where recovery is stopped. This lets us recover a backup to the point before a table was damaged or removed, capture the desired contents, and reintroduce ...