Even if a FILE devclass has dedup turned on, when the data is migrated, 
reclaimed, or backed up (backup stgpool) to tape, then the files are 
reconstructed from their pieces.

You cannot dedup on DISK stgpools.
DISK implies "random access disk" - e.g., devclass DISK.
FILE implies "serial access disk - e.g., devclass FILE.

But I think there is still an open question about collocation and 
deduplication.  Deduplication must be done using FILE stgpools, but FILE 
stgpools CAN use collocation.  I don't know what happens in this case.

..Paul

At 02:38 PM 6/21/2011, Prather, Wanda wrote:
>If it is a file device class with dedup turned off, yes.
>
>-----Original Message-----
>From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf 
>Of Mark Mooney
>Sent: Tuesday, June 21, 2011 2:29 PM
>To: ADSM-L AT VM.MARIST DOT EDU
>Subject: Re: [ADSM-L] Deduplication and Collocation
>
>So data is deduplicated in a disk storage pool but when it is written to tape 
>the entire reconstructed file is written out?  Is this the same for file 
>device classes?
>


--
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