Netbackup duplication questions

[FlyMountain]

Hi anyone, i have a few questions about Netbackup vaulting.

We are currently setting to backup our primary daily/weekly data copies to VTL, then vault to tapes. But we do have some issues. On both virutual and physical storage units, we have set the multiplexing to same number 4,  the "reserve multiplexing" is selected for duplication.

1. the duplication is running really slow on some jobs about 2MB/sec or even less, but not all. couldn't fingure out why? does the mulplexing slow the process down?

2. we have set three drives for vaulting, but sometime i only see one duplication job running. restart vaulting will re-kick off three duplications. is something not right on Netbackup?

3. we assumed the "reserve multiplexing" option on duplication will duplicate all multiplexed images to tapes together. but we did see different duplication jobs fought for same tape. don't understand why?

4. if we cancel any duplication job, will the images be picked up later or we will need to run vaulting again to have all iamges to be vaulted?

thanks in advance.

[RonCaplinger]

In general, I wouldn't recommend multiplexing backups to VTL.  There is an excellent document that can help explain the use of VTLs & NBU:

http://eval.symantec.com/mktginfo/enterprise/white_papers/b-whitepaper_using_virtual_tape_libraries_...

Assuming you have to use multiplexing, it is possible that the configuration based on the number of drives/other hardware in your VTL is affecting the throughput.  The above document can help figure out if the multiplexing is set correctly. 

So long as you have "Preserve Multiplexing" set on your NetBackup Vault profile, it *should* copy everything in the VTL volume together, unless your Vault filter is set to only duplicate one of the images from the virtual tape.  I could see that causing the throughput to slow down while it reads through unneeded fragments from the other three images. 

Do you also have "Allow multiple retentions per media" checked on the Master Server's "Media" properties?  That might be causing images with different retention periods to be written together, which could affect your multiplexing.

Other than these things, I can't see any direct reason from NetBackup that could restrict your VTL-to-tape performance.

[FlyMountain]

1. We don't have "Allow multiple retentions per media" checked on our master server.

2. Our source and target tape libraries did shared by three windows media servers with SSO option. will SSO effect any duplication perfromance?

3. We did notice the duplication on third media server much faster than other two. We do have more CPU power on third one. Will it made a big difference? (third one: 16GB RAM, 4*CPU 3.4GHZ, first and second: 16GB RAM, 2*CPU 3.0GHZ).

4. We enabled multiplexing on both VTL and tapes, set the same numbers.

[FlyMountain]

Just found we are having better performance (10 times faster) on vms003 than on vms002. vms003 does have better CPU power. does anyone have same experience?

vms003:       4*CPU 3.4GHZ, 16GB RAM
vms002:       2*CPU 3.0 GHZ, 16GB RAM

[FlyMountain]

Hi RonCaplinger,

What is "vault filter" and where i can find the setting?

thanks,