The following is based on the use of 10 tape for a backup rotation. This increases your daily file recovery length to ten days and increases your maximum recovery length to ten days.

This will also decreases the wear on the Monday through Thursday tapes. 

Grandfather/Father/Son

A second method, the Grandfather/Father/Son, works in much the same way with four rotating daily media. Each successive Friday uses a different backup media, three tapes for three successive Fridays. An additional three media set for three consecutive monthly backups is added to the rotation, this is the

Grandfather set.

The rotation strategy in its simplest form uses only 10 tapes. The daily tapes are reused each week. The three Friday tapes are rotated through the month and on the fourth Friday of the month one of the monthly (grandfather) tapes is used. This allows for a maximum possible recovery back to the third month, about 90 days after you have completed the full rotation and are one month into the second rotation. But the short-term daily backup is limited to only six days back.

However, by the end of the third month’s rotation you have now created an image of the end of five consecutive weeks (one of which is the monthly at the end of month two) and an additional monthly backup from the first month. This increases your ability to fail/fall back to a known good state in the event of an incident.

With these three extra monthly tapes you now have six good fall back points in addition to the four days of the week.