Right, with snapmirror, you don't have any significant lag to worry
about, and by listing entire volumes instead of qtrees, managing
snapshots for backing up over NFS is easy.  I do not believe you are
in any danger of backing up corrupt data if the snapmirror is
'transferring', but I would try to avoid that if possible. It's fine
to run backups in the 'quiescing' state.  I don't believe the method
used, be it NFS or NDMP has any bearing on this.

As far as which yeilds better performance, you just have to try that
for your environment.  Certainly, you'll want to stream your tape
drives by whatever means possible.  To perform a fair comparison,
don't go 3-way NDMP.  Go direct or through a SAN if you can. 
Traditionally, NDMP has yeilded better performance, but with recent
super high speed tape drives and netbackup w/NDMP continuing
*inability* to multiplex, you might be better of with NFS.

If you list entire volumes, all qtrees under it get backed up.  Use
separate policies for every volume so you know which snapshots to
manage in your <polname>.bpstart_notify and <polname>.bpend_notify
scripts.

Have you tried both methods?  You ought to be able to get a temporary
NDMP license from your sales rep.  What model filer are you using,
what types of drives are you using, and what data rates are you
seeing?  Just curious.

NDMP with netbackup is turning out to be disappointing.  No
checkpointing.  No drive sharing.  No multiplexing!

On Apr 2, 2005 6:42 AM, Algo Seeker <algorithm AT gmail DOT com> wrote:
> Well my problem is the mirrored volumes are always in a lag of 30
> minutes toan housr and ar in never idle state.  Now in that scenario,
> what would be the best way to backup.
> 
> I do have huge number of qtrees and I do not want to add those in my
> selection list and just want to add volumes.
> 
> Thanks
> On Apr 2, 2005 1:36 AM, Tim Berger <tim.berger AT gmail DOT com> wrote:
> > snapvaulted/snapmirrored volumes are treated no differently than any
> > other volume when using NDMP.  You specify qtrees in the include list.
> >  Snapshots are made on-the-fly.
> >
> > However, I recommend creating an ndmp_start_path_notify script to
> > check for volumes that are still "Transferring" data and fail out to
> > re-queue the job if this is the case.  This will avoid backing up
> > yesterday's vault data.  Adjust your media server's retries per hour
> > accordingly.
> >
> > On Apr 1, 2005 9:01 PM, Algo Seeker <algorithm AT gmail DOT com> wrote:
> > > I have searched the list and last postings were in Dec 2002. I want to
> > > backup a snapmirrored volume (the destination) using NDMP. Do I have
> > > to use the snapshot from the volume or there exist any better options.
> > >
> > > Also is there any body who is successful in doing a snapmirror to tape 
> > > option?
> > >
> > > Thanks
> > > _______________________________________________
> > > Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
> > > http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
> > >
> >
> > --
> > -Tim
> >
> 


-- 
-Tim