And that's why storage pool planning is very important.  The less re-duping,
hydrating, inflating you do the better.  Client data to a non-deduped (I
guess that would be a duped) pool that migrates to a deduped pool.  But
backup stgpool before the migration happens to avoid the re.

This is where I expect I'll be corrected: as long as the backup stg happens
before the deduplication process on the file devtype storage pool the
reduping won't have to happen. (we weren't really talking about collocated
copy pools were we?)

But then you wouldn't have a file devtype pool migrating to tape very often
anyway would you?  And if you did, that would only be in an emergency
situation (i.e., you ran out of room on disk).  And in that case why would
you collocate?

Ah, the words of someone that used to think he knew what he was talking
about!

Kelly J. Lipp
Elbert Colorado
719-531-5574


-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L@VM.MARIST.EDU] On Behalf Of
Prather, Wanda
Sent: Tuesday, June 21, 2011 12:27 PM
To: ADSM-L@VM.MARIST.EDU
Subject: Re: [ADSM-L] Deduplication and Collocation

Dedup only works in TSM storage pools that reside on disk (specifically
devtype=FILE pools).

If you have data that goes to a dedup pool, then gets migrated off to tape,
it is reduped (rehydrated, reinflated, whatever you want to call it.)

So collocation will still be in effect for that pool.

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L@VM.MARIST.EDU] On Behalf Of
Mark Mooney
Sent: Tuesday, June 21, 2011 2:17 PM
To: ADSM-L@VM.MARIST.EDU
Subject: [ADSM-L] Deduplication and Collocation

Hello,

I had a student ask me today "What happens if you have collocation turned on
for a storage pool that you are deduplicating?"  I did not know what to
answer because in my mind I thought "well, if the data is collocated then I
need to have a copy of that data on that client's tape, otherwise I am going
to be mounting another client's tape to get back a de-duped piece of data
which would negate the collocation"

I'm looking at the redbooks for this but I only see 6.1 and in 6.2 they
added client side dedup as well (which I also have questions about)

Can anyone shed some light on this?

Thanks!
Mooney

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