Tower of Hanoi rotation schedule

The Tower of Hanoi rotation schedule is a schedule, according to which the backup media sets are rotated a particular rotation pattern, as in the Tower of Hanoi puzzle. Currently, Handy Backup does not support the Tower of Hanoi rotation schedule.

The Tower of Hanoi backup rotation schedule stems from a puzzle, which was invented by Edouard Lucas, a French mathematician, in 1883. The game consisted of three pegs with eight discs placed on one of them. The task was to move all the discs to another peg, never placing a smaller disc under a larger one.

Just like in the game, the backup media sets are rotated through the entire backup process. Compared with the Grandfather-father-son rotation schedule, this one can employ more backup media sets and save a deeper backup history - the less often the backup media set is used, the older data version it has. This backup rotation schedule requires only five backup media sets to perform backups during a month every day, for instance.

How the Tower of Hanoi backup rotation schedule works

In this backup rotation schedule the first media set is used every second day, the second media set is used when the first set is not used and is used every fourth day, the third media set is used when neither of the previous sets are used and every eighth day and so on.

Each additional backup media set, added to the rotation, doubles the backup history, and is used only when the previous sets are not used, thus, the later a backup media set is added to the history, the less it is used and the older files it stores are. This enables one to have a deep backup history, but does not allow storing many recent backup copies, as a daily backup is erased in two days, for example.