Hi there,

For several Oracle 9i databases, we use RMAN and TSM for Databases to
store the backups in TSM.

This works fine. However, both database backups and archivelog
backups go to the same storagepool. The database is about
400 GB large, and this goes straight to tape. Archivelog
backups are much smaller, perhaps 1 GB each time. Archivelog
backups occur several times each day. These also go directly
to tape.

What this means is that one drive is occupied most of the time
by the archivelog backups. This is inconvenient; the drive could be
put to better use.

How I think this problem could be solved:

 * create a disk stgpool, say RMAN_DISK_POOL
 * create a tape stgpool, say RMAN_TAPE_POOL
 * define the MAXSIZE parameter for RMAN_DISK_POOL
 * define the NEXTSTGPOOL paramater for RMAN_DISK_POOL to point to
   RMAN_TAPE_POOL
 * point RMAN to RMAN_DISK_POOL

Will this work? Is there perhaps a better way of solving this problem?
(Is it even a problem at all?)

A possible problem with this setup might be that the TSM server
doesn't know the size of an RMAN-backup ahead of time, so
everything goes to RMAN_DISK_POOL and things break when too large
'files' end up in RMAN_DISK_POOL. (In our setup, the backup piece
size is quite large, much larger than the typical archivelog
backup. Choosing a correct value for MAXSIZE wouldn't be too
difficult.)

Thanks,
--
Jurjen Oskam