Steve,

Works fine as long as you're at least MP4.  Prior to that DSSUs would
stage the files in the filesystem sequentially regardless of retention
levels.  Thus if you're not mixing retention on a tape (but are on the
filesystem) you could have the situation where tapes are constantly
being mounted and unmounted, killing the advantages of the batch nature
of DSSU.

With 5.1 MP4 this has been fixed by separating the staging jobs by
retention level though you'll want to take note of MAX_STAGING_JOBS and
STAGING_JOB_KB_LIMIT parameters.

Other note is not to get too cheap of disk for this work, and make sure
there's enough of it.  One day's worth of problems can back you up
trying to stage to tape for several days afterwards.

G.

-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of Steven L.
Sesar
Sent: Thursday, April 27, 2006 10:09 AM
To: NetBackup Veritas
Subject: [Veritas-bu] DSSU/DSU experience

We're in the process of rearchitecting our BUR infrastructure. The most 
profound change will be the addition of disk storage, as we are 100% 
tape, right now. We're considering a few different disk technologies, 
such as VTL, DataDomain NAS heads, as well as traditional DSU/DSSUs.

I've heard anecdotal evidence that DSU/DSSU functionality in NBU 5.1 is 
less-than-stellar. Would anyone care to share their overall experience 
with  disk storage?

Thanks,

Steve

 

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