A schedule helps ensure that backups are done on a regular basis.
You should design one that accommodates the particular needs of
your information processing environment.
Here are three sample backup schedules that may be helpful in
designing an appropriate schedule for your needs.
When to do full backups |
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One possible backup schedule is to store your entire system to
tape at the end of each work day. The benefit of this schedule is that
in a recovery situation, you or the system operator must handle only one
tape set. The disadvantage is that, since all files (including those that have
not changed) are backed up every day, the amount of time and media needed to
complete the backup increases greatly.
When to use cumulative backups |
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Another strategy is to perform a full backup once per week,
and partial cumulative backups on all other work days. This strategy reduces
both time and media usage. In a cumulative backup, the date
is always the date of the last full backup and uses
the "greater than or equal" form ;DATE>=mm/dd/yy.
Following a cumulative backup stategy, you will need to handle
only two store tape sets to perform a full system recovery:
the most recent full backup set and the most recent partial backup set.
When to use incremental backups |
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In an incremental backup strategy, you perform a full backup once per week
and partial backups on all other workdays. However, since the date
of each partial backup is the date of the last partial backup
(not the date of the last full backup), only those files which have
changed are copied to tape.
The principal advantage to the incremental backup
strategy is that it uses the smallest amount
of time and media. The disadvantage is that, in the event of system recovery,
you must restore each tape set from the most recent full backup through
the most recent partial backup.
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