About pending requests for storage units
In the NetBackup Administration Console, expand Media and Device Management > Device Monitor. The following tape mount requests do not appear in the Device Monitor Pending Requests pane:
Requests for backups
Requests for a tape that is required as the target of a duplication operation
These requests are for resources in a storage unit and therefore are not for a specific volume. NetBackup does not assign a mount request for one storage unit to the drives of another storage unit automatically. Also, you cannot reassign the mount request to another storage unit.
If the storage unit is not available, NetBackup tries to select another storage unit that has a working robot. If NetBackup cannot find a storage unit for the job, NetBackup queues the job (a Queued state appears in the NetBackup Administration Console Activity Monitor).
You can configure NetBackup so that storage unit mount requests are displayed in the Device Monitor if the robot or drive is down. Pending requests appear in the Device Monitor, and you can assign these mount requests to drives manually.