> We have a client that wants to move their small occupancy nodes to their VTS
> and turn on collocation. Is there anyone using a VTS for TSM storage pool
> volumes? I would like to hear about your experiences. I'm just not
> comfortable with how appending data to an existing VTS volume works. Seems
> like you would be doing a lot of reclamation within the VTS.

We used to do this. Appending to existing tapes was ugly. The VTS staged
the old version of the virtual volume into disk cache, appended to it,
wrote the updated version to real tape, and discarded the old version.
We sometimes saw backup sessions waiting 45 minutes for a virtual volume
mount as the VTS dealt with a backlog of requests to stage virtual volumes
to disk. Tape reclamation also got to be painful.

We ended up using virtual tapes as initial destinations for backups, and
migrating to native 3590 tapes every morning. In essence we turned the
VTS into a wierd kind of disk storage pool.