How to configure storagepool reclamation with single tape drive


In general, reclamation of tape storage pool volumes requires at-least two tape drives, one for sending data from tape and other for receiving data from the first tape. This reclamation process is generally should be run in the time when TSM server is not busy, and this process can be done manually and also by defining admin schedules. TSM administrators has to make sure that atleast 2 tape drives are free during start of this reclamation process. However, some companies are reluctant to buy tape library with 2 or more number of drives due to various reasons, and TSM administrator has to reclaim the tapes regularly for efficient us of tapes. 

IBM Tivoli Storage Manager has a work around for this kind of situations. When a storage pool has only one mount point (that is, just one drive) available to it through the device class, data cannot be reclaimed from one volume to another within that same storage pool. To reclaim volumes in a storage pool that has only drive, you can define a reclamation storage pool (FILE devclass) and use it for temporary storage of reclaimed data.


Starting Reclamation with single Tape Drive

When the server reclaims volumes, the server moves the data from volumes in the original storage pool to volumes in the reclamation storage pool. The server always uses the reclamation storage pool when one is defined, even when the mount limit is greater than one.

If the reclamation storage pool does not have enough space to hold all of the data being reclaimed, the server moves as much of the data as possible into the reclamation storage pool. Any data that could not be moved to volumes in the reclamation storage pool still remains on volumes in the original storage pool.

Also Read: What is Offsite Reclamation ?

The pool identified as the reclamation storage pool must be a primary sequential storage pool. The primary purpose of the reclamation storage pool is for temporary storage of reclaimed data. To ensure that data moved to the reclamation storage pool eventually moves back into the original storage pool, specify the original storage pool as the next pool in the storage hierarchy for the reclamation storage pool. 

For example, if you have a tape library with one drive, you can define a storage pool to be used for reclamation using a device class with a device type of FILE as shown below

First, define the FILE deviceclass pool

define stgpool reclaimpool FILE maxscratch=100

Then define the tape storage pool with parameter reclaimstgpool=<poolname>

define stgpool ltopool1 LTO2 maxscratch=100 reclaimstgpool=reclaimpool

Finally, update the reclamation storage pool so that data migrates back to the tape storage pool:

update stgpool reclaimpool nextstgpool=ltopool1

You can specify multiple concurrent reclamation processes for a primary storage pool with one drive by using the RECLAIMSTGPOOL parameter. If multiple concurrent processing is not desired, specify a value of 1 for the RECLAIMPROCESS parameter on the DEFINE STGPOOL or UPDATE STGPOOL commands.


Single Drive reclamation in mixed media Library

In a mixed-media library, reclaiming volumes in a storage pool defined with a device class with a single mount point (that is, a single drive) requires one of the following:

Also Read: Tape Library related Interview Questions
  1.  At least one other drive with a compatible read/write format.
  2. Enough disk space to create a storage pool with a device type of FILE




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