Hi Leigh,

I have brought in 1TB of SATA disk for random disk storage pools.  Would
you happen to know if there is a maximum number of volumes that can be
defined per storage pool?  If I have a disk pool that is 800GB, how many
volumes should I have defined?  What should the max. size of each volume
be?  If anyone has any ideas, please let me know.  Thanks!


********************************
Joni Moyer
Highmark
Storage Systems
Work:(717)302-6603
Fax:(717)302-5974
joni.moyer AT highmark DOT com
********************************



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Joni

The following URL is to the TSM V5.3 Technical Guide Redbook.

If you go to section 3.4.6, it discusses some changes in TSM 5.3 that
lend themselves to 'disk only backups'
Obviously, if you're not at 5.3 yet, then they may not be of use to you.

I personally would consider SATA disk as a possible replacement to
sequential tape, but I would still use good quality fast disk as
traditional 'random' disk pool to stage the nightly backups. I think
that it is widely recognised that significantly 'slicing up' the
diskpool into a large number of smallish volumes, greatly improves
performance (certainly on the backup). I believe that this is because of
the 'multi-threaded' nature of TSM.

I would imagine that the config for the best performance of SATA disk as
random TSM backuppool, would be to configure each SATA disk as a single
TSM volume within the backuppool and ensure that you have enough SATA
disks/backuppool volumes as you have sessions in at the same time.

However, with SATA disk capacity increasing rapidly, it's not efficient
to have a 100 x 250GB SATA disks (100 TSM volumes) sitting in your
backuppool, that only ever get 10% utilised.

I must state that this is just my opinion, I have no direct experience
with SATA disks.

Leigh