428
NetBackup System Administrator’s Guide - Windows NT Server
B
Prioritizing the Worklist
The worklist typically contains jobs from different classes and schedules.
NetBackup checks for the following when determining the order in which to
run the backups that are in the worklist:
1. Highest priority backup as determined by the class Priority attribute.
Backup jobs from the class with the highest priority runs first.
For example, assume that clients named Ant and Beetle are in different
classes and that Ant is in the class with the highest priority. Here, the jobs
for Ant always run before the Beetle jobs.
2. Backup with a retention level that is the same as a tape that is currently
mounted.
If class priorities are equal, NetBackup tries to start a backup job that has
the same retention period as a tape that is currently mounted. This reduces
delays in waiting for tape mounts.
For example, assume that Ant and Beetle are in the same class but their
schedules have different retention periods. Also, assume that the Ant job is
the most overdue. However, a tape is mounted that has the same retention
level as Beetle.
Here, the Beetle job runs first because it can be stored on a tape that is
already mounted, thus making the most efficient use of resources. If there is
another drive of the correct type available, a tape will be mounted on that
drive for the Ant job.
3. Most overdue backup job.
If the priorities and retention level are equal, NetBackup prioritizes backups
according to how long they are overdue. The clients that are the most
overdue have the highest priority.
NetBackup determines how long a backup is overdue by subtracting the
backup frequency (on the schedule) from the length of time since the last
successful backup for that client.
For example, assume that Ant and Beetle have backup jobs that are in the
same class and have the same retention level. Also assume that the
schedules for these backup jobs both have a frequency of 1 day. If the last
NetBackup 3.2 System Administrator's Guide for Windows NT
NetBackup 3.2 System Administrator's Guide for Windows NT