Grandfather-Father-Son

Grandfather-father-son is one of the most widely used backup rotation schedules.

According to this backup rotation schedule the backup media sets are rotated through incremental backups that are performed daily, and full backups that are done weekly and monthly.

First of all, from one to four media sets are designated for incremental daily backups. As daily incremental backup backs up the least of the data, compared with other backup sessions in this backup rotation schedule, any of these media sets can be referred to as a 'son' media set. These media sets are reused each week on the designated day.

Secondly, full backups are performed weekly - daily incremental backup is not performed on this day. As the first backup needs to be a full backup, the scheme is started on Friday, the day of the full backup. Consequently, the media set used on Friday can be referred to as a 'father' media set.

Furthermore, on the last business day of the month a full backup is performed to a new media set, which can be referred to as a 'grandfather' media set. These media sets are designated for specific months throughout the year.

As the backup data size can vary, each of these media sets may be a single backup medium or multiple backup media sets. To complete a quarterly backup rotation, a total of twelve backup media sets are required when using this basic backup rotation schedule. Sometimes one may wish backup history needs to be saved - in this case a media set with a full backup is taken from the rotation and replaced with a new media set.