ADSM-L

Re: [ADSM-L] Vtl questions

2010-06-15 17:00:04
Subject: Re: [ADSM-L] Vtl questions
From: Paul Zarnowski <psz1 AT CORNELL DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU
Date: Tue, 15 Jun 2010 16:58:44 -0400
TSM 6.2 clients can do deduplication, but only if the target storage pool is 
FILE.  So if you really want to do client-side (aka source-mode) deduplication, 
you should consider FILE instead of VTL.  VTL will only do server-side 
(target-mode) deduplication.  If you do deduplication in TSM, it will require 
more server resources.  If you do deduplication in a VTL, you will be 
off-loading that processing from your TSM server.  Tradeoffs, tradeoffs, 
tradeoffs.  I'm afraid there is no "one size fits all answer".  IMHO, it makes 
more strategic sense to let TSM do the deduplication, since it knows most about 
the data, but the devil is always in the details.

..Paul


At 04:51 PM 6/15/2010, Remco Post wrote:
>On 15 jun 2010, at 22:30, Lee, Gary D. wrote:
>
>> Our installation is tsm v5.5.4 under suse linux sles 9 running as a guest 
>> under vm 5.3.
>>
>> We are out of disk on our ds8100, and, rather than license more disk, I am 
>> considering a vtl and illiminate our onsite 3494.
>> So, I am looking for a place to start.
>> Sepaton seems very expensive, so wondering what else others are using.
>>
>> 1. What, if any, vtl is used in your tsm installation?
>>
>
>none.
>
>> 2. How does a file device class compare with a vtl in terms of manageability 
>> and useability?
>>
>
>FILE is easy, even boring. A VTL is very useful if you want to do LAN-free 
>and/or dedup (and not upgrade to 6.x yet). I'd think that FILE is even a bit 
>easier than a VTL (relabelscratch). A VTL is more versatile, but also a lot 
>more expensive.
>
>In your environment (VM running the TSM server), only FILE is the officially 
>supported option of the two. Tape (even virtual tape) access is only supported 
>on physical servers. This doesn't mean it doesn't work, just that if you even 
>need support... don't call IBM, as it is now.
>
>
>> Thanks for any insites.
>>
>>
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>
>--
>Met vriendelijke groeten/Kind Regards,
>
>Remco Post
>r.post AT plcs DOT nl
>+31 6 248 21 622


--
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

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