Multiple reclamation processes run concurrently, which makes better use of your available tape drives or FILE volumes.
You can specify one or more reclamation processes for each primary sequential-access storage pool, copy storage pool, or active-data pool by using the RECLAIMPROCESS parameter on the DEFINE STGPOOL and UPDATE STGPOOL commands.
Each reclamation process requires at least two simultaneous volume mounts (at least two mount points) and, if the device type is not FILE, at least two drives. One of the drives is for the input volume in the storage pool that is being reclaimed. The other drive is for the output volume in the storage pool to which files are being moved.
When you calculate the number of concurrent processes to run, you must carefully consider the resources that you have available. You must consider the number of storage pools that are involved with the reclamation, the number of mount points, the number of drives that can be dedicated to the operation, and (if appropriate) the number of mount operators available to manage reclamation requests. The number of available mount points and drives depends on other Tivoli® Storage Manager and system activity and on the mount limits of the device classes for the storage pools that are involved in the reclamation.
For more information about mount limit, see: Controlling the number of simultaneously mounted volumes
For example, suppose that you want to reclaim the volumes from two sequential storage pools simultaneously and that all storage pools involved have the same device class. Each process requires two mount points and, if the device type is not FILE, two drives. To run four reclamation processes simultaneously (two for each storage pool), you need a total of at least eight mount points and eight drives. The device class for each storage pool must have a mount limit of at least eight.
If the device class for the storage pools being reclaimed does not have enough mount points or drives, you can use the RECLAIMSTGPOOL parameter to direct the reclamation to a storage pool with a different device class that has the additional mount points or drives.
If the number of reclamation processes you specify is more than the number of available mount points or drives, the processes that do not obtain mount points or drives wait indefinitely or until the other reclamation processes complete and mount points or drives become available.
The Tivoli Storage Manager server starts the specified number of reclamation processes regardless of the number of volumes that are eligible for reclamation. For example, if you specify ten reclamation processes and only six volumes are eligible for reclamation, the server starts ten processes and four of them complete without processing a volume.
Multiple concurrent reclamation processing does not affect collocation. For more information, see How collocation affects reclamation.