Fix issue causing DRM volumes to be checked out without being updated in DRM

It is difficult to word a requested problem fix as an RFE, but that is what I've been asked by support to do, so here is my best effort.

Use of the “Wait” parameter of the BACKUP STGPOOL command is currently the best option to ensure that disk storage pool backups complete before tape storage pool backups. It also allows multiple runs of backups of the same storage pool when, as is often the case, it is necessary to run these processes while client backups are running, to ensure that all backed up data is protected for disaster recovery purposes.

The following 2 statements are paraphrased, but are presented as they were explained to me by support while working on the referenced PMR.

Currently, TSM reserves volumes used in the BACKUP STGPOOL process and does not release them until the process completes, when the “Wait” parameter is used at invocation of BACKUP STGPOOL.

Within the MOVE DRMEDIA process, TSM actually runs a CHECKOUT LIBVOLUME and MOVE DRMEDIA (to update the DRM status of the volume) as separate tasks within the MOVE DRMEDIA processes. The MOVE DRMEDIA task cannot update the volume while a reservation exists.

The problem that can result is that, when a reservation occurs after CHECKOUT LIBVOLUME task runs and is still in place when the MOVE DRMEDIA (for update) task runs, a volume is checked out without being updated in Disaster Recovery Manager (DRM).

I propose that this problem be addressed in the best way possible, which is why I have asked that this be an APAR for problem fix, not just documentation. As such I would leave the exact resolution up to development, but here are some suggestions:

1. Create a reservation that prevents the BACKUP STGPOOL from reserving volumes that are already being processed by the MOVE DRMEDIA process, even if only by the CHECKOUT LIBVOLUME task.

2. At the very least, provide a message that indicates that a volume has been checked out as part of the MOVE DRMEDIA process, but it was not updated in DRM.