OK May be I was not clear what we would use the SATA or FC  ATA for would
be the primary disk storage pools for nightly backup window
then next morning we would be migrating the backup data to tapes ( FC 3592
jaguar drives ), current primary storage pools are Enterprise class
(shark disks) and our disk storage pool is currently 1.7 TB for nightly
backup that is what we call cache pool, on one TSM Server and another
TSM server we have 1.6 TB of primary storage pool, then we have a small TSM
server that has 1/2 TB of primary storage pool. In all we backup up 513
clients nightly with the 3 TSM servers and data that is backed up runs
between 2.7 TB to 3.2 TB. in a backup window of 6 to 8 hours.  We do have
about 100
Oracle RMAN backups included in the backup window running TSM TDPO backups.
If you need more information please let me know.

My concerns are that we will slow down the client backups when we have so
many clients running in a small backup window.
If we use SATA or FC ATA drive for the primary disk storage pool.
Thanks

Justin Case









             Jin Bae Chi
             <Jbaechi AT CSCC DOT EDU
             >                                                          To
             Sent by: "ADSM:           ADSM-L AT VM.MARIST DOT EDU
             Dist Stor                                                  cc
             Manager"
             <[email protected]                                     Subject
             .EDU>                     Re: How are TSM admins using SATA
                                       for cache pools?

             07/12/2005 08:24
             AM


             Please respond to
             "ADSM: Dist Stor
                 Manager"
             <[email protected]
                   .EDU>






Justin,

You may need to tell us more about your configuration and how much data and
how long you need to keep the data before any migration with cache turned
on/off. As you mentioned, you may not need the enterprise class stg for
these particular diskpools unless your SLA requires certain strictness in
performance. Because of the nature of SATA, write I/Os will be troublesome
in any case, so make sure that the controller have enough cache and destage
it later. Some people make mistake buying with single controller config,
but remember that you can't afford to lose it during client backups. Look
for the new SATA II which comes with a lot of fixes and also,

TSM takes pretty much any disks that OS sees as available so consider
giving multiple diskpools. Depending on what tape storage you have, but
writing direct to tape device today is not a bad idea in many cases, so
consider not only diskpool for immediate writes, but also tape devices such
as FC LTO2 or LTO3. For the better pricing, ATA drives with proper RAID
config could be considered.

When configured correctly, SATA drives will be performing as good as other
types of disks. I've been running and happy with them for a while for TSM
and other applications. Hope this helps.


Gus


>>> justin.case AT DUKE DOT EDU 07/11/05 10:01 PM >>>

How are TSM admins using SATA disks for cache pools ?

What type of SATA disks are being used and at what raid levels ?

How satisfied are you with the backup times with SATA disks for cache pools
on TSM ?

We are looking at SATA for TSM cache pools is why the questions because
we are using enterprise class storage for cache pools on TSM currently at a
high cost.

Looking for cheaper disks for TSM cache pools.
Thanks

Justin Case
TSM Administrator/Storage Administrator
IT Analyst  OIT Infrastructure Support
334 Blackwell Street
2nd floor  Suite 2108 Durham,NC 27701
Duke University
Email: justin.case AT duke DOT edu