Interesting. We have had similar issues with NBU DSSUs.

The HPSS (www.hpss-collaboration.org/hpss) seems to be the best option, 
combined with ACSLS, for our environment.

We have HPSS running with other equipment in one of our scientific 
divisions (www.nersc.gov) and they just rave about its abilities.

I note it supports (server,disk and offline storage on the server-side) 
Solaris and AIX. But the client-side support is there for many, many 
other platforms, from Cray T3 UNICOS to Linux, where there are a variety 
of tools to use (such as htar and other HSI unix-like tools).

We are thinking about a hybrid NBU/HPSS approach, allowing data to be 
staged in various areas of storage, based on user-customizable rules. 
Backups would be on top of the ACSLS and HPSS.

Just my $.02.

Certainly not the cheapest solution, but it does give more manageability 
to at least larger SAN environments like ours.

hth

Cheers!

--Chris



Ambrose, Monte wrote:

>DSSU sizing is really important.  If the Disk runs out then you start
>getting status 84's and jobs fail.  This seems reasonable except that
>NBU does not free up the space for the failed jobs until the jobs are
>restarted. If the job is a large one then you could get several more
>backup failures from other jobs before the job retries and cleans up the
>old space from the failed backup.  
>
>The cleanup process for disk images already copied to tape is not very
>efficient.  I also have had to create a script that checks for disk
>backup images that are successfully copied to tape so that I can clean
>up the images to make room for the new backups coming in.  The script
>also checks for high and low watermarks and emails/pages if the disk
>space gets lower than 90%
>
>I also agree that you want to use fast disk for this.  We have tested
>with a few different levels and are now using SAN attached RAID10
>
>I am at NBU 5.1MP4.  I am looking at moving to NBU 6.0 MP2 to take
>advantage of all the new DSSU improvements and features.
>
>Monte 
>
>-----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 Johnny
>Oestergaard
>Sent: Thursday, April 27, 2006 10:44 AM
>To: 'Steven L. Sesar'; 'NetBackup Veritas'
>Subject: RE: [Veritas-bu] DSSU/DSU experience
>
>I have been using DSSU since 5.1 came out.
>But I have primarily used it for very slow clients so that I didn't
>block my
>tapedrives with these backups.
>
>It has been working really fine, except the lack of configuration and
>performance/tuning. And it has been really easy to use.
>
>I have upgraded to 6.0 MP2 now, and there are a lot of nice new stuff in
>6.0
>regarding DSSU, but I haven't had that much time to check it out. But it
>seems to perform better and there are also more configuration options.
>Not
>that I couldn't make a 1 meter list of things I would like to have.
>
>DSU's I have only used for testing, so no comments from me on that. But
>when
>I looked at it DSSU seemed to me to be a much better solution. At least
>in
>our installation.
>
>Have never used VTL, so also no comments on that.
>
>/johnny
>
>-----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: 27. april 2006 19:09
>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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