I think this is due to be changed in an upcoming MP for NBU 6....to allow 
multiple streams off one DSSU.   I'm sure I heard they were doing 
something about that.

William D L Brown




andrew.x.smith AT jpmchase DOT com 
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu
23-Mar-2006 15:59
 
To
"Paul Keating" <pkeating AT bank-banque-canada DOT ca>
cc
veritas-bu AT mailman.eng.auburn DOT edu
Subject
RE: [Veritas-bu] on the subject of disk based backups....







Yeah, for me the biggest weakness of the NBU DSSUs. 




"Paul Keating" <pkeating AT bank-banque-canada DOT ca> 
23/03/2006 15:48 
        
        To:        <andrew.x.smith AT jpmchase DOT com> 
        cc:        <veritas-bu AT mailman.eng.auburn DOT edu> 
        Subject:        RE: [Veritas-bu] on the subject of disk based 
backups....



excellent info...Now that you mention it....my one small DSSU I have 
configured to offload to a specific tape pool, so I should have known 
that. 
That definately sways me in the direction of VTL then. 
-----Original Message-----
From: andrew.x.smith AT jpmchase DOT com [mailto:andrew.x.smith AT jpmchase DOT 
com] 
Sent: March 23, 2006 8:30 AM
To: Paul Keating
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] on the subject of disk based backups....


Hi Paul, 

 from my experience what you say about DSSU is incorrect, a single DSSU 
cannot stage the data off to multiple tape tape pools - if you have a 
requirement to stage to different tape pools you need to have a at least 
one DSSU per tape pool, 

               cheers Andy. 




"Paul Keating" <pkeating AT bank-banque-canada DOT ca> 
Sent by: veritas-bu-admin AT mailman.eng.auburn DOT edu 
23/03/2006 13:05 
        
       To:        <veritas-bu AT mailman.eng.auburn DOT edu> 
       cc:         
       Subject:        [Veritas-bu] on the subject of disk based 
backups....




I'm also interested in thoughts regarding VTL vs DSSU. 
DSSU interests me mostly because I can write multiple jobs at once without 
any regard for tape pool, mpx or not, retention, etc..... 
...then it all gets sorted out to appropriate tapes during the destaging 
VTL still presents itself to NBU as a tape, so each virtual tape drive 
must be licensed with Veritas, in additional to the physical tape drives 
(unless the VTL is run inline, though there could be issues there 
regarding estimated compression, etc.) 
Just a couple things off the top of my head. 
Just wondering who is using DSSU, adn who is using VTL, adn why you made 
that choice....ie.what were the key requirements for your environment that 
made one option better than the other. 
Paul