Unforutnatly that does not seem to be the case.

As a test I queued up a number of backup jobs. Waited a few seconds to get
them in the queue, then started two restore requests.

The results are interesting.

I have 4 drives. Each drive is currently processing a backup. (ie: 4 backups
underway). The two restores show as 'active', not 'queued'. This means that
I have 4 drives, but 6 active jobs. (no multiplexing anywhere)

As backups finish, it proceeds to another backup. The two active restores
(with no drives to do them) are not taking priority.

I have been watching this test now for close to half an hour and am
consistently seeing the same thing. Restores are not taking priority. They
are taking their 'standard' place in a FIFO queue.

Hold up.. There we go... The restores just took place with a few jobs in the
queue yet. It seems one of the active backup jobs filled the tape and did a
request for a new tape. The restores sliped in then.

My guess is this. Let me know how it sounds.

NetBackup is written with multiplexing in mind. For this reason, a restore
does not take priority over when jobs finish on a tape, but when a tape
drive becomes free due to a tape swap (ie: filled tape, no more backups for
that retention, etc...). All the restores show as 'active' because they are
in a quasi-active state. Waitign for a tape drive, but not being processed
until it is available.

This means that that restores get placed at the front of the 'tape use
queue', not the front of the job queue.

Unfortunatly, this can lead to some *very* large delays in restores being
processed. Since it seems NetBackup is capable of 'pausing' a backup to do a
restore (it must do this to eject the tape at EOM anyway) I wonder if it is
possible to tell NetBackup to do this 'mid tape' as well....

Jason

> -----Original Message-----
> From: David A. Chapa [mailto:david AT xbpadm-commands DOT com]
> Sent: October 11, 2001 11:18
> To: Tim McMurphy; Veritas BU
> Subject: RE: [Veritas-bu] Restore priority
> 
> 
> That's the normal operation. NBU is not pre-emptive, so it 
> won't kill a
> backup, but when one completes the restore will begin.  At 
> least that's what
> we were taught back in the OpenVision days.
> 
> david
> 
> <><><><><><><><><><><><><><><><><><><><>
> David A. Chapa
> NetBackup Consultant
> DataStaff, Inc.
> http://www.consulting.datastaff.com
> 847 413 1144
> ---------------------------------------
> NBU-LSERV AT datastaff DOT com - Adv. Scripting
> http://www.xbpadm-commands.com
> 
> -----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 Tim
> McMurphy
> Sent: Thursday, October 11, 2001 9:22 AM
> To: Veritas BU
> Subject: RE: [Veritas-bu] Restore priority
> 
> 
> That is strange. We had the same situation here a couple of 
> months ago and
> all 8 drives were busy doing backups. As soon as a drive 
> became available
> (backup filled a tape) the restore ran then the backup resumed.
> 
> I was quite impressed how smoothly it went.
> 
> -----Original Message-----
> From: Jason Ahrens [mailto:AhrensJ AT psi DOT ca]
> Sent: Thursday, October 11, 2001 7:40 AM
> To: Veritas BU
> Subject: [Veritas-bu] Restore priority
> 
> 
> Yesterday night, we had a system go down. The system was rebuilt and a
> restore was started to bring back the data.
> 
> The restore was started just minutes after the backup window 
> opened. This
> means taht the queue was full of backup jobs. It also 
> appeared that the
> restore did not take priority over the backups, and it would 
> have taken
> hours to wait for the queue to clear. This was not acceptable 
> and we ended
> up killing all the backup jobs so the restore could happen, 
> and requeued all
> the backups.
> 
> I'm thinking there has to be a better way.
> 
> How can I instruct NetBackup to consider restores at a higher 
> priority than
> backups, so that when the first free drive and required tape 
> becomes free,
> the restore will occur. I would't ask that backups in progress are
> halted/suspended for the restore, just that the restore go to 
> the top of the
> queue.
> 
> Thanks
> 
> Jason
> 
> --
> Jason Ahrens
> Systems Administrator/Backup Specialist
> PSINet Limited
> http://www.psi.ca
> The Internet SuperCarrier
> 
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