Re: anyone using ATA disk systems

We have not done a lot of testing on this, so this can not be taken as a
definitive statement. With that said, the following sums up our current
thoughts on this:

- Because there is no reclamation for random access storage pools, (a)
disk fragmentation is definitely a concern, and (b) aggregates are not
rebuilt, so as objects within an aggregate expire, that space is not freed
up until all objects in the aggregate have expired. This can cause
inefficient utilization of the disk space over time.

- FILE device classes could be used, but represent configuration and
performance concerns.

- While such an environment is technically possible, it is not the
intended TSM usage model, and we do not recommend it at this time.

- We continue to study this issue.

Regards,

Andy

Andy Raibeck
IBM Software Group
Tivoli Storage Manager Client Development
Internal Notes e-mail: Andrew Raibeck/Tucson/IBM@IBMUS
Internet e-mail: storman AT us.ibm DOT com

The only dumb question is the one that goes unasked.
The command line is your friend.
"Good enough" is the enemy of excellence.


Steve Schaub <Steve.Schaub AT HAWORTH DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
05/23/2003 07:08
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: anyone using ATA disk systems



Hey Andy R, how about getting some Tivoli developers on the server-side
to throw some answers at this.  I have spoken with many users, business
partners, & architects and have yet to get a consistant picture.  Some
insist that using one huge diskpool works fine, others say the disk
format leads to disastrous fragmentation and the only way to go is file
class volumes, still others say not to even try this approach.  Maybe a
Tivoli white paper specifically addressing disk-only primary storage
pools would give a definitive answer?

-----Original Message-----
From: Talafous, John G. [mailto:Talafous AT TIMKEN DOT COM]
Sent: Friday, May 23, 2003 9:26 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: anyone using ATA disk systems


We too are considering a mass expansion of our storage pools to
implement Disk to Disk backup via TSM. The reason is to enhance recovery
times. The Nexsan ATABeast is under consideration.  We currently have
about 40TB backed up to TSM storage pools. I am thinking of bringing in
MANY TB of ATABeast so that we can discontinue migration to tape. I am
curious as to what happens internally in TSM when you drive your storage
pool utilization to, say, 80% and hold it there?  Are there any
performance penalties?  Any cautions? Any real world experience?  How
much ATA should I consider?

TIA,
John G. Talafous              IS Technical Principal
The Timken Company            Global Software Support
P.O. Box 6927                 Data Management
1835 Dueber Ave. S.W.         Phone: (330)-471-3390
Canton, Ohio USA  44706-0927  Fax  : (330)-471-4034
talafous AT timken DOT com           http://www.timken.com


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