Sample Backup Schedules

The following three sample backup schedules illustrate how the three backup types interact:

  • Network A has a base backup scheduled for every Sunday and an incremental backup scheduled for all the other days of the week. All the backups are performed at 2:00 am. If on Sunday at 1:00 am, all the data on the network is lost, it would take 7 tapes (1 base plus 6 incrementals) to restore the entire Enterprise.

  • Network B has a base backup scheduled for every Sunday and a differential backup scheduled for every other day of the week. All the backups are performed at 2:00 am. If on Sunday at 1:00 am, all the data on the network is lost, it would take 2 tapes (1 base plus 1 differential) to restore the entire Enterprise.

  • Network C has a base backup scheduled for every Sunday, a differential backup scheduled for every Thursday, and an incremental backup scheduled for every other day of the week. All the backups are performed at 2:00 am. If on Sunday at 1:00 am, all the data on the network is lost, it would take 4 tapes (1 base, 1 differential, and 2 incrementals) to restore the entire Enterprise. Remember, the differential backup copies all the data that has changed since the last base backup. Therefore, the Thursday differential backup backs up all the data that was changed on Monday, Tuesday, and Wednesday in addition to any data that changed on Thursday.

For another example, suppose a network has a base backup performed monthly. If incremental backups alone were used to cover the remainder of the days, 31 tapes could be required to restore the entire Enterprise (assuming 30 days in the month). Even if only one differential is performed, let’s say on the 15th, the maximum number of tapes required to restore the network is 16 (1 base, 1 differential, and 14 incremental). Interspersing differential backups greatly reduces the number of tapes required.

Note. More than one backup may fit on a tape. However, added protection is gained by spreading backups over tapes. The preceding examples assume that you are using a separate tape for each backup.

Last updated