Tivoli® Storage Manager lets you restrict the number of mount points (volumes or files) that can be concurrently opened for access by server storage and retrieval operations. Attempts to access more volumes than the number indicated causes the requester to wait.
When selecting a mount limit for this device class, consider how many Tivoli Storage Manager processes you want to run at the same time.
Tivoli Storage Manager automatically cancels some processes to run other, higher priority processes. If the server is using all available mount points in a device class to complete higher priority processes, lower priority processes must wait until a mount point becomes available. For example, Tivoli Storage Manager cancels the process for a client backup if the mount point being used is needed for a server migration or reclamation process. Tivoli Storage Manager cancels a reclamation process if the mount point being used is needed for a client restore operation. For additional information, see Preempting operations.
If processes are often canceled by other processes, consider whether you can make more mount points available for Tivoli Storage Manager use. Otherwise, review your scheduling of operations to reduce the contention for resources.
To specify the number of concurrently opened mount points, use the MOUNTLIMIT parameter when you define the device class or update its definition.