09-23-2010 04:48 AM
We had an urgent restore request at the tame that the nightly backups were running. The restore queued and then sat there waiting for a drive to become available. when this job had waited for an hour or so, we had to abort some of the backups in an effort to free up the tape drive for the restore.
I thought that the restore job having a priority of 90000 would mean that NBU would try and free up a drive as soon as it can and then start the restore.
The answer is probably no, however, does anybody know of a nice clean way of forcing a restore job to get to a drive without having to resort to spending an hour or so aborting running backups and then restarting them afterwards?
09-23-2010 04:57 AM
Have also found that it does jump the queue as it were if the media fills for the current backup jobs - it jumps in before the media change.
It does not force the currently running jobs "off", but merely waits for an appropriate time when a drive is essentially free. The restore request will be fulfilled prior to the backups in this regard.
I think you've probably found the 'cleanest' solution - suspend the jobs using one of the tape drives (& possibly any that are queued waiting for that media - they will probably get in before the restore as the media is already loaded!) which will then allow the restore to use that drive. Or wait until the backups request a new tape at which point the restore should jump in.
09-23-2010 06:18 AM
DOCUMENTATION: Job Priority is not used if resources are available.
http://www.symantec.com/business/support/index?page=content&id=TECH56110
Snippet:
"...
When jobs are initiated, there is no prioritization used on the first job to go active if all current resources are available. Once a job receives the resources that it needs, the job become Active and begins.
However, if resources are busy (for example, tape drives in use) then the jobs are queued. A lower priority job may use an available resource over a higher priority job that requires a different resource that is not yet available.
...."
09-24-2010 04:55 AM
This is what we do:
1: Reduce the number of "Maximum concurrent write drives" in the STU config.
2: Disable scheduling with nbpemreq -suspend_scheduling
3: Wait 5 minutes - This allow the recourse broker to pick up the new concurrent write drives.
4: (optional) Kill all jobs running on one tape drives to free it up.
5: Restore starts
5: Resume scheduling with nbpemreq -resume_scheduling. This is OK, because the concurrent write drive is now decremented and we have a free drive.
6: Increase the "Maximum concurrent write drives" to it's previous value.
09-24-2010 08:08 AM
You can also designate one drive only to restores. I know it could be wasting of resources because drive is idle most of the time, but you are always sure that you can perform restore without killing jobs etc..
09-24-2010 08:16 AM
I know of no way to "reserve" one drive for restores.
09-24-2010 08:23 AM
as intimated by Nicolai.
e.g. 4 drives, max concurrent write 3 so one always available. STUs not used by restores.
09-24-2010 08:37 AM
I know there is no option to set it directly and maybe it's good idea to submit enhancement but what happens when there is 10 tape drives configured in NB but only 9 in backup storage unit ? In my opinion NB will use 10th drive during restore when 9 are busy. I'll check as soon as I can.
09-24-2010 08:41 AM
If you have more than one Media server and storage units for each
say I have 4 drive
media1 has stu of 3 drives
media 2 has stu of 3 drives
backups run on both media servers
media1 takes 3 drives
media 2 takes 1 drive
No drives left.
now say I setup
media 1 with 1 drive
media 2 with 2 drives
leaving 1 drive free for restore
a restore starts using media 2 for the restore
that stu is already busy using both drives in the stu so no drives avail for restore.
------------
Explain to me where I am wrong on this. I seem to have a miss understanding how this is works, As I see no drives avail for the restore.
09-25-2010 01:33 AM
With SSO and all drives shared it's not possible, you're right. But option to designate specific drive only for restores would be very useful.