[Veritas-bu] Fronting backups with disk then bleeding off to tape.

On Tue, Jun 20, 2006 at 12:47:17PM -0400, Justin Piszcz wrote:
> Nice, the only part I worry about is what if it cannot bleed off to
> tape fast enough and the disk fills up? Has this happened to you?

Yes, this can happen.  With 5.x, the job will fail with a status 84.
With 6.x, NBU will suspend the job, flush the disk to tape, and then
resume the job.

        .../Ed

> 
> On 6/20/06, Paul Keating <pkeating at bank-banque-canada.ca> wrote:
> > Yes, common in many environments.
> > Yes, you can use multiple streams from a DSSU to tape....works quite
> > well in practice.
> > 6 is supposed to work better than 5, in that you can group DSSUs, like
> > regular STUs, so if one fills up, backups go to another with available
> > space.
> >
> > When you destage to tape from disk, the data is supposed to stay on disk
> > untill free space is required....Netbackup attempts to keep the DSSU as
> > full as possible, so that data can be restored from disk rather than
> > tape. The data is only purged from disk when another backup tries to
> > write to the disk and determines the disk is full...then several of the
> > oldest images on disk, that have already been destaged to tape, will be
> > purged from disk to make room for the new backup.
> >
> > Paul
> >
> > --
> >
> >
> > > -----Original Message-----
> > > From: veritas-bu-bounces at mailman.eng.auburn.edu
> > > [mailto:veritas-bu-bounces at mailman.eng.auburn.edu] On Behalf
> > > Of Justin Piszcz
> > > Sent: June 20, 2006 12:06 PM
> > > To: veritas-bu at mailman.eng.auburn.edu
> > > Subject: [Veritas-bu] Fronting backups with disk then
> > > bleeding off to tape.
> > >
> > >
> > > Does anyone do this with a massive amount of data?  Also, I
> > > noticed with
> > > 5.1MP4 its possible to use multiple streams to bleed from
> > > disk->tape but I
> > > was wondering how well this worked practice.
> > >
> > > How many people bleed off to tape using 5.1MPx?
> > > Using 6.0?
> > >
> > > How well does it work under 6 vs. 5? I know there is a
> > > watermark feature.
> > > Also, how come when I bled data off to tape under 5.1MP4, it did not
> > > remove the images from disk?  Must I manually purge that data?
> > >
> > > Thanks,
> > >
> > > Justin.

-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts at ewilts.org