Cause

By design reclamation processing (checking for reclaimable volumes) runs on the Tivoli Storage Manager server at startup and then at 60 minute intervals from the last completion time. If a Tivoli Storage Manager Administrator issues an update storage pool command migration thresholds are checked and migration will start if there is a valid next storage pool and the percent migratable is above the high migration percentage. The server traverses through each storage pool in the storage pool hierarchies starting migration processes as needed.

Because the last storage pool in any storage pool hierarchy does not have a next pool, migration cannot be run for this pool. When this is the case, if the storage pool is a sequential pool then the check for migration on this last pool will turn into a check for reclamation. In other words an update storage pool will indirectly, through migration checking, trigger reclamation checking in the last storage pool in a given hierarchy (if that last pool is a sequential pool).

If a given storage pool hierarchy has one or more intermediate sequential pool levels before the lowest level pool, reclamation will not be checked/triggered by an update storage pool command for these pools. Migration values will be checked for these pools because they have a next pool, but reclamation for them will not be checked until the standard 60 minutes reclamation check next expires.