For common practice de-dup is not a tape oriented process. It is usually to
reduce data on disks.
One concern would be the amount of tape mounts required to restore data in the
event of a DR scenario.
As the article has stated there are not many "global" de-dup products yet. We
have been able to implement some dedup on specific applications, for instance
E-mail attachments and it has worked out fairly well. However, it primarily was
to reduce the size of the Storage Groups of our Exchange cluster, in the event
of a DR scenario, which is on tier 1 storage. And the de-dupped attachments are
now on tier 2. It reduced our SGs by 1/3. The exchange SGs backups are retained
based on legal requirements and replicated. The attachments are not.
I also tested Data Domain and was very unimpressed by the numbers I saw. It had
very little impact on our largest amounts of data. Imaging, Exchange and DB
dumps. But that is also the hardest type of data to de-dup.
My two cents.
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
madunix
Sent: Wednesday, June 24, 2009 11:37 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Dedupe
However, for my thoughts of Dedupe it could be interesting for those
who need to decrease the number of tape cartridges, but they could
suffer signifigannt CPU and I/O spec. for dedupe processing, and one
issue i was thinking about is a fauiler or if one part is corrupted,
i.e. many files would be affected by loss of common chunk, and what
about encryption is it compatible with encryption.
Thanks
madunix
On Wed, Jun 24, 2009 at 11:23 PM, Howard
Coles<Howard.Coles AT ardenthealth DOT com> wrote:
> I think, and I may be wrong, that the desired response was along the
> lines of validating the articles in the links, or giving an opinion on
> Dedup itself.
> However, I think Allen's opinion of the requester is based on the recent
> "Disaster Recovery" thread, where apparently, being pointed to the docs
> wasn't sufficient.
>
> The accusation of vagueness appears to be valid for this question as
> it's not really clear what is wanted.
>
> Opinion on the links? Fairly good info, especially the compiling of the
> different VTL vendor's published dedup numbers into one chart. However,
> with any information like that personal follow up and verification (to
> keep up with current numbers and specs) is always recommended.
>
> Opinion on Dedup? Have none, haven't done it yet, but would like to.
>
> See Ya'
> Howard
>
>
>> -----Original Message-----
>> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
>> Of lindsay morris
>> Sent: Wednesday, June 24, 2009 1:07 PM
>> To: ADSM-L AT VM.MARIST DOT EDU
>> Subject: Re: [ADSM-L] Dedupe
>>
>> Short and clear answer about de-dupe:
>>
>> It depends.
>>
>> Hope this helps.
>>
>> ------
>> Mr. Lindsay Morris
>> Principal
>> www.tsmworks.com
>> 919-403-8260
>> lindsay AT tsmworks DOT com
>>
>>
>>
>>
>> On Jun 24, 2009, at Jun 24, 11:33 AM, goc wrote:
>>
>> > somewhat right but still over the top in my humble opinion ... so,
>> > whatever
>> > ...you could simply answer with short and clear answer about dedupe
>> > if you
>> > know anything, or simply
>> > ignore the question ... so your behavior is really odd.
>> >
>> > On Wed, Jun 24, 2009 at 5:09 PM, Allen S. Rout <asr AT ufl DOT edu> wrote:
>> >
>> >>>> On Wed, 24 Jun 2009 13:00:52 +0200, madunix <madunix AT GMAIL DOT COM>
>> >>>> said:
>> >>
>> >>
>> >>> I was reading the following on the net regarding dedupe, can I
> have
>> >>> your opinion about the dedupe?
>> >>
>> >>
>> >> You may note that you get a somewhat sparse, even frosty, response
>> >> from this list. I'll let you know why I, in particular, don't
>> choose
>> >> to respond to most of your queries.
>> >>
>> >> You ask questions in a sufficiently vague manner that the
>> appropriate
>> >> answer is a long explanatory discourse. But you don't appear to
>> >> welcome pointers to the authoritative discourse: the docs. This is
>> >> fairly normal "newbie" behavior; nothing odd.
>> >>
>> >> But your web presence indicates you feel yourself to be enough of a
>> >> TSM pro to put it on your CV. From someone of that competence
>> level,
>> >> the right questions are phrased something like:
>> >>
>> >>
>> >> Hi, I'm doing X, with Y sorts of machines, and I encountered Z. Is
>> >> this what you expect, how are you-all doing this, etc..
>> >>
>> >>
>> >> The interesting social-group distinction is that, in one
>> >> communication
>> >> you are:
>> >>
>> >> + offering some advice and feedback to those more newbie than you.
>> >> This is important: you're giving before you're asking.
>> >>
>> >> + going out on a limb a bit, to show you have faith in your past
>> >> opinions, while offering them for correction
>> >>
>> >> + displaying enough context that those contemplating a reply know
>> how
>> >> to phrase their answer.
>> >>
>> >>
>> >> The terse, broad requests feel more like 'will you do my homework
>> for
>> >> me?', but I'm a known curmudgeon. So, whatever.
>> >>
>> >>
>> >> - Allen S. Rout
>> >> - Get off my lawn!
>> >>
>
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