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SLPs (duplication) not using all Tape Drives

Created: 25 Nov 2012 • Updated: 27 Nov 2012 | 6 comments
This issue has been solved. See solution.

Hello All,

I've 2 tape libraries with a total of 3 drives (one library has a single drive) and SLPs configured to first backup the data to disk and then duplicate to tape.

However I notice that though the SLPs are distributed across the 3 drives, one drive is not being used at all although backup jobs are in queue.

My environment in brief is as follows:

1. One Master cum Media server

2. One Media server

3. One SAN Media server

Each server above is configured to use the 3 drives. I'm not sure why all the 3 drives are not being utilized as this would speed up my tape backup process which is currently going into backlog till a week later.

Any help would be much appreciated.



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Marianne's picture

Difficult to say without having insight into details of STU and SLP configuration.

Please share output of :

bpstulist -g -U

nbstl -L

Please also have a look at this post where silimilar problem was resolved with  TAPE_RESOURCE_MULTIPLIER setting in LIFECYCLE_PARAMETERS : 
Remember to use "= " sign in NBU7.5 for LIFECYCLE_PARAMETERS entries, e.g.

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
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mph999's picture

Following on from the outstandingly excellent post from Marianne ...

I have seen a few times a very strange issue where one drive out of x is never used.  Nothing is found in the logs that is any use, and the drive is not listed as 'reserved' in nbrbutil -dump output.

Oddly, the resolution is to run nbrbutil -resetall (not with any backups running though) so this could be worth a go.


Regards,  Martin
Setting Logs in NetBackup:
Adnan F's picture

Thank you Marianne & Martin.

Marianne, I've set the TAPE_RESOURCE_MULTIPLIER value to 2. Will monitor for the results and check. Also uploaded the output from the commands.

Martin, I'll check out the command when backup jobs are not running in my environment.



bpstulist_result.txt 4.85 KB
nbstl_result.txt 42.32 KB
Marianne's picture

You need to fix the Media server name for these STU's:  

Label:                Tape_One_Drive_Netbackup_Master
Host Connection:      _STU_NO_DEV_HOST_
Label:                Tape_One_Drive_Nbmedia
Host Connection:      _STU_NO_DEV_HOST_
Label:                Tape_One_Drive_Nbmedia_LDT1
Host Connection:      _STU_NO_DEV_HOST_

You also  have a Storage Unit Group configured but it is nowhere specified in any of the SLPs?

You should be able to cut down on the amount of SLPs if you use STUG instead of specific STUs.
Created STUG for Media Manager STUGs for Master, Media and San Media server.

Symantec's recommendation is to introduce SLPs slowly and also to limit the number of SLPs.

See Best practice guide for SLP and AIR.


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Adnan F's picture

Hello Marianne,

Thank you so much, that fixed the issue. Below is what I did after your recommendations:

1. Fixed the Media server names for the missing host connections

2. Configured 3 STUGs for each media server (in a way that single STUG has access to all 3 drives)

3. Limited the SLPs to just 3 (this I guess I'll have to monitor for the next week, till the first cycle is complete)

Marting, thank u 4 the cmd, I'll remember it for future.


Adnan F

Marianne's picture

Thanks for sharing the good news!

Supporting Storage Foundation and VCS on Unix and Windows as well as NetBackup on Unix and Windows
Handy NBU Links