The Grandfather media
rotation strategy requires the following:
Table: Grandfather media rotation strategy
Number of media required
Overwrite protection period
The Grandfather method is
one of the most common media rotation strategies. It is simple to
administer and comprehensive enough to allow easy location of files
when they need to be restored.
In the Grandfather
scenario, four media are used Monday through Thursday for
incremental or differential backups; another three media are used
every Friday for full backups.
The remaining 12 media
are used for monthly full backups and are kept offsite.
Figure: Grandfather Backup Strategy
The Grandfather strategy
is recommended because it offers a good media number to storage
life ratio (19 media/1 year). It is also easy to modify if you want
to incorporate more media. For example, you could perform a full
backup on the last Saturday of the month to archive