Volumes with the access value of offsite are eligible for reclamation if the amount of empty space on a volume exceeds the reclamation threshold for the copy storage pool or active-data pool. The default reclamation threshold for copy storage pools and active-data pools is 100%, which means that reclamation is not performed.
When an offsite volume is reclaimed, the files on the volume are rewritten to a read/write volume. Effectively, these files are moved back to the onsite location. The files might be obtained from the offsite volume after a disaster, if the volume has not been reused and the database backup that you use for recovery references the files on the offsite volume.
The server reclaims an offsite volume as follows:
- The server determines which files on the volume are still valid.
- The server obtains these valid files from a primary storage pool or, if necessary, from an onsite volume of a copy storage pool.
- The server writes the files to one or more volumes in the copy storage pool or active-data pool and then updates the database. If a file is an aggregate with unused space, the unused space is removed during this process.
- A message is issued indicating that the offsite volume was reclaimed.
During offsite reclamation, active-data pools cannot be used to obtain data.
For a single storage pool, the server reclaims all offsite volumes that are eligible for reclamation at the same time. Reclaiming all the eligible volumes at the same time minimizes the tape mounts for primary storage pool volumes.
Tip: You can reclaim space in offsite volumes
that are controlled by a z/OS® media
server.If you are using the disaster recovery manager, see Moving copy storage pool and active-data pool volumes onsite.