Reference Topics
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backup for Ant ran 25 hours ago and the last backup for Beetle ran 26 hours
ago, then both clients are overdue for a backup. However, the Beetle job is
the most overdue and will run first.
This approach ensures that a backup that was not successful during its
previous backup window has priority over backups that were successful.
This is important on a busy system where the backup window can
sometimes close before all backups can begin.
Factors Affecting Backup Time
The time NetBackup requires to complete a backup is an important factor in
scheduling. This is particularly true for sites that deal with large amounts of
data. For example, the total backup time can exceed the time allotted to
complete backups and interfere with normal network operations. Longer
backup times also increase the possibility of a problem disrupting the backup.
The time to back up files can also give you an indication of how long it takes to
recover them.
The following formula shows the major factors that affect backup time:
Backup = Total data x Compression Device Delays
Time Transfer rate (optional)
Total data
The amount of data you must back up depends on the size of the files for each
client in the class you are backing up. It also depends on whether it is a full or
incremental backup.
• Full backups involve all the data. Therefore, a full backup usually takes
longer than an incremental.
• Differential-incremental backups include only the data that has changed
since the last full or intervening incremental.
• Cumulative-incremental backups include all the data that has changed since
the last full backup.
With both differential- and cumulative-incremental backups, the amount of
data in the backups, depends on the frequency with which files change. If a
large number of files change frequently, incrementals are larger.
NetBackup 3.2 System Administrator's Guide for Windows NT
NetBackup 3.2 System Administrator's Guide for Windows NT
