Backups

Backup copies are required when:

Data is (accidentally) deleted
The main storage medium fails
As a corporate data repository

To optimise the backup process we can distinguish the following types of backup:

Full backup (contains a complete copy of the data - also called level-0)
Incremental backup (often multiple levels - also called level-n)

Every level contains differences from previous level.

Ensure that:

Backup copies are stored in a different, but safe location (off-site)
Periodically the ability to recover a single file or a complete disk is verified