Joni,

If you read Ben Bullock's recent posting, I agree with everything he has
said. I would definitely use raw disk volumes (in a Unix world).


Leigh

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Joni Moyer
Sent: 17 August 2005 20:31
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: [ADSM-L] AW: [ADSM-L] Migration Speed Has Plummeted

Hi Leigh,

I have just added EMC fibre channel disk from a CX700 in the following
pieces of physical disk under the filesystem /tsmdev/stgpool1

CHRS044     /tsmdev/stgpool1

lun 175           100 GB
lun 178           100 GB
lun 181           100 GB
lun 184           100 GB
lun 187           100 GB
lun 190           100 GB
lun 193           100 GB
lun 199           100 GB
lun 204           100 GB
lun 210           100 GB

Total       1000 GB

When you stated using many small TSM disk storage pool volumes, would
anyone happen to know what a good, acceptable size TSM volume would be?
Thanks!

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



             "Leigh Reed"
             <L.Reed AT MDX.AC DOT UK
             >
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             Sent by: "ADSM:           ADSM-L AT VM.MARIST DOT EDU
             Dist Stor
cc
             Manager"
             <[email protected]
Subject
             .EDU>                     Re: AW: [ADSM-L] Migration Speed
                                       Has Plummeted

             08/17/2005 10:39
             AM


             Please respond to
             "ADSM: Dist Stor
                 Manager"
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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