As part of a major upgrade, I am considering moving some TSM DB backups
to FILE volumes. LTO4 tapes hold a terrabyte, and the incrementals, in
particular, are wasting a LOT of tape. I'm thinking of doing full DB
backups to tape, and incrementals to disk FILE volumes.

The manual says you can back up the TSM Database to either TAPE, or to
Virtual Volumes on another TSM server. It doesn't mention FILE volumes.
I seem to remember somebody long ago saying you should not consider
that. OK, so what's wrong with backing up the TSM Database to FILE
volumes?

This would be what I suppose might be safe:

Do not use a local filesystem. The FILE volumes used for DB backup
should reside on an NFS-mounted filesystem, which can also be mounted by
some other system. A separate physical location would be nice. This
should be on the same NFS server which you also use to back up the
Volume History and Device Config files. On all systems that can mount
this NFS filesystem, it should be mounted at the same mount point as on
the TSM server system. That is so the DB Backup volume names in the
Volume History File are still valid.

Are there any other pitfalls I am not forseeing here?

Having said that, though, I have not noticed any performance difference
between Virtual Volumes on another server, and a mounted NFS filesystem.
The network is the speed limitation. It's just that Virtual Volumes are
more complicated, and thereby more problem prone when a junior staff
member is the one called in a disaster to do a TSM DB restore, while I'm
camping in the mountains.

Roger Deschner      University of Illinois at Chicago     rogerd AT uic DOT edu
               Academic Computing & Communications Center
======I have not lost my mind -- it is backed up on tape somewhere.=====