Job Priorities

[MikeM11]

Hi all,

I have an issue whereby SLP's are taking priority over backups causing job failures due to resources being unavailable.  I thought I had resolved this for one policy by raising the priority of that policy from the default value 0 to 1000 but think I have misunderstood.

We are running NetBackup 7.1.0.4 on Windows 2008 R2 Enterprise for Master/Media servers and all Clients are either MP3/MP4.

The default job priorities are set as:

Backups - 60000

Duplication - 50000

Most backup policies have a priority of 0 in the attributes which I take to now mean "use the default job priorities" in the Master server attributes.  SLP's have a duplication job priority of 99.

There are 3x policies with a priority of 1000.

Do I need to update the backup policies to a value higher than 50000 to resolve this or is there something else going on?

Many thanks, Mike

[Andy_Welburn]

I have an issue whereby SLP's are taking priority over backups causing job failures due to resources being unavailable.

Are they actually taking priority or is it just that they are utilising the resources when your normal backups are due to start?

Just because a job has a higher priority does not mean that it will jump in & stop lower priority jobs if they are already in progress. Also, if a lower priority job is currently using resources & another lower priority job is queued waiting for those same resources, then that second lower priority job will *still* get preference over any queued higher priority jobs as its resources are already 'loaded'.

Or:

The following scenarios present situations in which a request with a lower priority may receive resources before a request with a higher priority:

• A higher priority job needs to unload the media in a drive because the retention level (or the media pool) of the loaded media is not what the job requires. A lower priority job can use the media that is already loaded in the drive. To maximize drive utilization, the Resource Broker gives the loaded media and drive pair to the job with the lower priority.

• A higher priority job is not eligible to join an existing multiplexing group but a lower priority job is eligible to join the multiplexing group. To continue spinning the drive at the maximum rate, the lower priority job joins the multiplexing group and runs.

• The Resource Broker receives resource requests for jobs and places the requests in a queue before processing them. New resource requests are sorted and evaluated every 5 minutes. Some external events (a new resource request or a resource release, for example) can also trigger an evaluation. If the Resource Broker receives a request of any priority while it processes requests in an evaluation cycle, the request is not evaluated until the next evaluation cycle starts.

http://www.symantec.com/business/support/index?page=content&id=HOWTO34237

[MikeM11]

Hi Andy, thanks for the response.

It certainly does appear to be that they are taking priority but obviously there are a few complications.  We have a 15 drive HP EML to cope with multiple Clients backing up straight to tape and handling the SLP requests from over 50 jobs.  They are all relatively similar in terms of multiplexing requirements and retention levels so I would expect they to work harmoniously together.

What I see on a Monday morning is that over 75 jobs/SLP's are queuing for 15 tape drives and it appears that the SLP's get these resources first.  However the backup jobs do start later and so I was hoping to leapfrog the queue and get things backed up first and suplicated afterwards.

Am i just kidding myself or is this possible?

Thanks, Mike

[Andy_Welburn]

What I see on a Monday morning is that over 75 jobs/SLP's are queuing for 15 tape drives and it appears that the SLP's get these resources first.  However the backup jobs do start later and so I was hoping to leapfrog the queue and get things backed up first and suplicated afterwards.

Which confirms it!

Don't use SLP so not sure if this is an option or not, but can you restrict the number of tape drives that your SLPs utilise? e.g. create another STU which limits maximum number of concurrrent drives & then apply that to your SLPs?

Altho' that may not be an option as you may have more than "75 jobs/SLP's ... queuing for 10 tape drives"

Only way we managed to 'leapfrog' anything with the way that NB's priorities work is by suspending enough jobs (including queued) that are utilising resources that could then be made available for your normal backups.

PS: how do you "suplicate" in NetBackup? (Sorry couldn't resist the typo!)

[MikeM11]

That would make a lot of sense.

We are looking into increasing our multiplexing value anyway but may test reducing the number of "concurrent write drives" associated with a storage group.  My concern around that it that they may still end up using all the drives anyway as multiple calls are made to the SLP but worth testing.

P.S. Suplicating is an advanced feature that is undocumented...I'm not meant to talk about it ;)