PostgreSQL 12 High Availability Cookbook - Third Edition

More backup types

pgBackRest actually supports three types of backup. We only used fully because this is a demonstration of a single backup, but this is what the documentation has to say about all of them:

• full: All database cluster files will be copied and there will be no dependencies on previous backups.
• incr: This is incremental from the last successful backup.
• diff: This is like an incremental backup but always based on the last full backup.

Incremental backups only contain differences since the last successful backup, hence creating a chain of much smaller backups than we'd expect from storing every PostgreSQL file. Consider what happens when we take an incremental backup and check the repository:

If we compare that to the full backup ...