How you connect to the disk storage (i.e., SCSI or SAN) doesn't matter.  This 
goes more to the issue of how blocks within the volumes are laid out on the 
spindles.  formatting them one at a time will cause the blocks to be laid out 
in a more sequential fashion, so that when TSM references the blocks, they will 
be referenced in a more sequential fashion (assuming you are doing mostly 
sequential I/O).

..Paul


At 02:02 PM 10/20/2010, Zoltan Forray/AC/VCU wrote:
>Thanks for the affirmation.  This is what I have been seeing/experiencing. 
> As soon as I can empty the stgpool (5TB), I will define fixed volumes and 
>see how much difference that makes.   I am aware of the issue of 
>single-threading the define/formats to not fragment them, however I wonder 
>how much that really matters in a SAN?
>Zoltan Forray
>TSM Software & Hardware Administrator
>Virginia Commonwealth University
>UCC/Office of Technology Services
>zforray AT vcu DOT edu - 804-828-4807
>Don't be a phishing victim - VCU and other reputable organizations will 
>never use email to request that you reply with your password, social 
>security number or confidential personal information. For more details 
>visit http://infosecurity.vcu.edu/phishing.html
>
>
>
>From:
>Markus Engelhard <markus.engelhard AT BUNDESBANK DOT DE>
>To:
>ADSM-L AT VM.MARIST DOT EDU
>Date:
>10/20/2010 09:20 AM
>Subject:
>[ADSM-L] Lousy performance on new 6.2.1.1 server with SAN/FILEDEVCLASS 
>storage
>Sent by:
>"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
>
>
>
>Hi Zoltan,
>
>my experience has been: use fixed size preformatted volumes, and be sure 
>to
>format them sequentially, even if it seems to take a hell of a time. But
>then, it´s a one-time action and highly automated, so just don´t try to
>boost "performance" here. Make sure no one else is bogging perfs, SAN guys
>sometimes tend to put all kinds of unassorted loads on one storage array
>producing massive hot-spots during TSM activities.
>
>Kind regards,
>
>Markus
>
>
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--
Paul Zarnowski                            Ph: 607-255-4757
Manager, Storage Services                 Fx: 607-255-8521
719 Rhodes Hall, Ithaca, NY 14853-3801    Em: psz1 AT cornell DOT edu