A full backup is a backup that can be restored independently of any other backup. A full backup will be performed if the last full backup is older than the specified frequency. Between full backups, all backups are incremental, saving only changes made since the previous backup.

### Syntax

FREQUENCY := <int>[DWM]

'D' is for Days. 'W' is for Weeks. 'M' is for Months.

### Examples

      3D      three days
      2W      two weeks
      1M      one month

### Technical Implications

Incremental backups are useful because they are fast and efficient. But restoring an incremental backup requires retrieving the volumes of all backup sessions made before it, up to and including the full backup that started the chain. The longer the backup chain, the more time it will take to restore.

Very long backup chains are inefficient and more vulnerable if something goes wrong as links in the chain depend on one another.

If you backup daily, and do a full backup monthly, your backup chains will consist of a full backup with at most 30 incremental backups linked to it. If you backup more frequently (e.g., hourly) you may want to reduce the full backup frequency to every few days.