The level of multiplexing should not affect de-duplication at all.
There are other reasons not to multiplex to a VTL, but de-dupe is not
one of the reasons.

You need to use the 7.3.? feature that allows you to set a maximum
number of streams per device.  The "target sessions" is a minimum, not
max.  This new setting ("maximum sessions" or something like that) is
actually a maximum.  Set the max to 1 for the VTL drives, and to some
other number for the real drives.

---
W. Curtis Preston
Backup Blog @ www.backupcentral.com
VP Data Protection, GlassHouse Technologies 

-----Original Message-----
From: EMC NetWorker discussion [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On
Behalf Of Joel Fisher
Sent: Monday, August 27, 2007 8:02 AM
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Subject: [Networker] paralellism

Hey Guys,

We're looking at possibly purchasing an inline dedup VTL.  But as you
would expect it dedups best if you can send one stream per virtual drive
to the VTL.  I can't figure out how to limit the parallelism to that
particular autochanger but allow it to our real library.  It would be
really nice if target sessions would limit to that number, but it
doesn't. The only thing I can think to do is possibly have one save
group the a save group parallelism = number of drives.  But that seems
really limiting to be able to only have one group.

Am I missing something that can be done to just turn off parallelism for
a particular drive/library?

Thanks!

Joel

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