IBM TSM - How to reclaim offsite tapes for reuse
If you have many offsite tapes particularly in relation to how much data your are backing up then the offsite tapes may be under utilised.
First check the utilisation of the volumes in your offsite copy storage pools by running the following SQL query.
select a.stgpool_name,a.volume_name,a.pct_utilized,a.pct_reclaim from volumes a,stgpools b where a.stgpool_name=b.stgpool_name and b.pooltype='COPY' order by a.stgpool_name,a.pct_utilized
You should get output similar to the following.
STGPOOL_NAME VOLUME_NAME PCT_UTILIZED PCT_RECLAIM ------------------ ------------------ ------------ ----------- OFFSITE VOL049L2 0.9 99.1 OFFSITE VOL097L2 1.9 98.0 OFFSITE VOL011L2 2.0 97.9 OFFSITE VOL083L2 2.0 98.0 OFFSITE VOL031L2 2.2 97.7 OFFSITE VOL067L2 2.5 97.7 OFFSITE VOL038L2 2.6 97.3 OFFSITE VOL046L2 3.7 96.2 OFFSITE VOL045L2 4.8 95.7 OFFSITE VOL077L2 5.2 95.0 OFFSITE VOL058L2 8.5 92.1 OFFSITE VOL040L2 8.7 91.2 OFFSITE VOL030L2 9.5 90.9 OFFSITE VOL041L2 17.6 82.4 OFFSITE VOL035L2 27.1 73.8 OFFSITE VOL091L2 31.1 69.1 OFFSITE VOL080L2 38.6 61.3 OFFSITE VOL095L2 51.9 48.4 OFFSITE VOL044L2 52.5 47.6 OFFSITE VOL016L2 54.1 47.0 OFFSITE VOL022L2 86.2 13.8 ORA_OFFSITE VOL078L2 38.8 61.1 ORA_OFFSITE VOL076L2 40.7 59.2 ORA_OFFSITE VOL033L2 50.5 49.4 ORA_OFFSITE VOL034L2 51.9 48.0 ORA_OFFSITE VOL053L2 68.3 31.6 ORA_OFFSITE VOL002L2 71.7 28.2 ORA_OFFSITE VOL061L2 0.0 0.0 ORA_OFFSITE VOL073L2 46.2 0.0 ORA_OFFSITE VOL096L2 52.6 47.3 ORA_OFFSITE VOL081L2 0.0 0.0 ORA_OFFSITE VOL001L2 5.7 94.2 ORA_OFFSITE VOL029L2 59.4 40.5 ORA_OFFSITE VOL006L2 91.3 8.6
As you can see there are quite a few tapes under 10% utilised.
Next check the reclamation threshold for your offsite copy pool. To do so type the following.
q stg OFFSITE f=d
Substitute OFFSITE with the name of your offsite storage pool.
You should get output similar to the following.
Storage Pool Name: OFFSITE
Storage Pool Type: Copy
Device Class Name: LTOCLASS
Estimated Capacity: 395,489 G
Space Trigger Util:
Pct Util: 0.4
Pct Migr:
Pct Logical: 98.7
High Mig Pct:
Low Mig Pct:
Migration Delay:
Migration Continue:
Migration Processes:
Reclamation Processes: 1
Next Storage Pool:
Reclaim Storage Pool:
Maximum Size Threshold:
Access: Read/Write
Description: Storage pool
Overflow Location:
Cache Migrated Files?:
Collocate?: No
Reclamation Threshold: 50
Offsite Reclamation Limit: No Limit
Maximum Scratch Volumes Allowed: 999
Number of Scratch Volumes Used: 21
Delay Period for Volume Reuse: 0 Day(s)
Migration in Progress?:
Amount Migrated (MB):
Elapsed Migration Time (seconds):
Reclamation in Progress?: Yes
Last Update by (administrator): admin
Last Update Date/Time: 07/17/2009 11:30:21
Storage Pool Data Format: Native
Copy Storage Pool(s):
Continue Copy on Error?:
CRC Data: No
Reclamation Type: Threshold
Note that the Reclamation Threshold is set to 50%. If it is set to 100% then reclamation is switched off.
With a reclamation threshold of 50% any tapes with 50% or less utilisation should get reclaimed. Therefore our tapes under 10% utilised should have been reclaimed. If they don't it maybe that the reclamation process doesn't get time to reclaim them, always trying to reclaim the more heavily utilsed tapes first.
A quick way of reclaiming these tapes is to increase the reclamation threshold of the storage pool to 90%.
To set the threshold to 90% for this storage pool type the following.
upd stg OFFSITE reclaim=90
Substitute OFFSITE with the name of your offsite storage pool.
The next time reclamation runs it will reclaim any tapes that have a utilisation of 10% or below.
These will be available to check in to the onsite library as scratch.
However you may want to set the threshold lower than 90% for the long term.