Also check to see what sort of filesystem this is.  

The last time I looked at archive solutions that left stub files (and it
has been a while) they often required you to use their own special
filesystem type.  You'd hate to go through all the work only to find out
NBU doesn't recognize the filesystem.  (Maybe less of an issue with NAS
based since NBU presumably sees it as an NFS mount on the host you've
put the FS on.)

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of A Darren
Dunham
Sent: Friday, October 17, 2008 11:14 AM
To: VERITAS-BU AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] stub file backup/restore performance

On Fri, Oct 17, 2008 at 09:49:38AM -0400, Jay wrote:
> 
> We are looking into a couple of archiving solutions for our NAS
> environment which will leave small stub files (0-8K) on the original
> volume. Those volumes will continue to be backed up via NDMP. I'm a
> little leary of trying to backup thousands of small files. Has anyone
> out there seen a performance hit when backing up or restoring these
> stubs?

My guess is that there are two areas where you might see the effect.

#1) On the NDMP host, you may have a per-file cost at backup time.
    Network Appliance filers use a 'dump' scheme.  As the number of
    files increase, the time spent in phase I increases.  On volumes
    with millions of files, that can be many hours before significant
    data starts moving.

#2) Each filename has to be sent to the catalog.  As the files get
    smaller, the catalog pipe/machine/disk are all working harder
    relative to the actual data path.  When I'm running lots of fulls, I
    can overwhelm my catalog machine thanks to some volumes with huge
    numbers of files.  Keep an eye on your catalog disk performance.  If
    it gets too slow, you'll slow down the backups.

-- 
Darren
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