System Administration Guide: Devices and File Systems

Considerations for Scheduling Backups

A backup schedule is the schedule that you establish to run the ufsdump command. This section identifies considerations to think about when you create a backup schedule. This section also includes sample backup schedules.

The backup schedule that you create depends on the following:

How Often Should You Do Backups?

If you do not need to minimize time requirements and the number of media that is used for backups, you can do full backups every day. However, this backup method is not realistic for most sites, so incremental backups are used most often. In this case, you should back up your site enough to so that you can restore files from the last four weeks. This schedule requires at least four sets of tapes, one set for each week. You would then reuse the tapes each month. In addition, you should archive the monthly backups for at least a year. Then, keep yearly backups for a number of years.

Backup Interval Terms and Definitions

The following table describes backup interval terms and definitions.




Creates a temporary image of a file system. 

Full backup 

Copies a complete file system or directory.  

Incremental backup 

Copies only those files in the specified file system that have changed since a previous backup. Incremental backup types include the following: 

  • Daily, cumulative – Copies a day's worth of file changes on Monday. Then, overwrites Monday's backup with file changes from Tuesday, Wednesday, and so on.

  • Daily, incremental – Copies a day's worth of file changes so that you have distinct tapes of Monday's changes, Tuesday's changes, and so on.

  • Weekly cumulative – Copies the files that have changed during the week and includes the previous week's file changes.

  • Weekly incremental – Copies the files that have changed during the week since the previous weekly backup.