IBM E16RMLL-I Implementation Guide - Page 292
Reclamation
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tsm: ATLANTIC>q stg Storage Device Estimated Pct Pct High Low Pool Name Class Name Capacity Util Migr Mig Mig Pct Pct OLDRDATA DISK 12 G 0.0 0.0 80 30 Next Storage Pool ----------TAPEDATA 6.5.13 Reclamation Data on tapes in sequential access storage pools will eventually expire, leaving portions of the tapes with empty areas (also known as fragmentation). Over time, fragmentation can cause many tapes to have very little valid data on them. Reclamation is the process where the valid data on a number of tapes is consolidated onto a smaller number of tapes. The tapes that are emptied by the reclamation process are returned to scratch status for reuse. See "Data Storage" in IBM Tivoli Storage Management Concepts, SG24-4877. Reclamation is usually scheduled during a period of low activity because it can be a very intensive operation, for both the server and the tape drives. However, you can run reclamation manually using the reclaim stgpool command. The reclaim stgpool command takes a number of options. To set the reclamation threshold, set the THreshold parameter to a value between 50 and 99. The THreshold value represents the percentage of reclaimable space on a volume. To check the amount of reclaimable space on a volume, run a query volume command. Subtract the value in the Pct Utilized column from 100 to obtain the percentage of reclaimable space on the volume. The other parameter required for reclaim stgpool is the DUration parameter. DUration is the length of time reclamation will run for on the selected storage pool. If there is nothing to reclaim, or reclamation finishes before the duration is over, the process exits. Example 6-40 shows an example of the reclaim stgpool command. Example 6-40 Reclaim stgpool command tsm: ATLANTIC>reclaim stgpool offdata threshold=85 duration=30 tsm: ATLANTIC>q act Date/Time 03/02/2006 11:00:28 03/02/2006 11:00:28 03/02/2006 11:00:28 Message ANR2017I Administrator ADMIN issued command: RECLAIM STGPOOL offdata threshold=85 duration=30 (SESSION: 5) ANR0984I Process 1 for SPACE RECLAMATION started in the BACKGROUND at 11:00:28. (SESSION: 5, PROCESS: 1) ANR2110I RECLAIM STGPOOL started as process 1. (SESSION: 262 IBM Tivoli Storage Manager Implementation Guide