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SLP Duplication jobs on different media servers

Created: 20 Mar 2009 • Updated: 23 May 2010 | 5 comments

Hey All,

We have duplication jobs set up in our Storage LifeCycle Policies (SLP).  Our SLP is configured to create a backup to an Advanced Disk Staging Group (DSG).  Our DSG has two media servers in it.  The SLP is then set to make two duplicate copies, one for onsite vaulting and one for offsite vaulting.  The dupe jobs get queued and then run when a media server has a tape drive available.  Often, the media server that NetBackup picks to read the data from the DSP and the one it picks to write the data to the tape drive are two different media servers, although each has access to the exact same resources (both DSG and tape drives).  Is there any way to force the duplication job to use the same media server for both reads and writes so our data isn't bottlenecked by the network?  Obviously, we don't want to specify the media server, we just want the jobs to pick the same server.

Thanks for the comments,

Mike Smith

Comments 5 CommentsJump to latest comment

Douglas_A's picture

Actually its supposed ot use the same media server for read and write. This is a bug pre 6.5.3 that was supposed to be fixed in 6.5.3 and 6.5.3.1 so i would suggest contacting symantec and having them go over the situation with you and possibly upgrade or maybe provide you a solution.

good luck

Best of Luck,

Doug

Please remember to mark the most valuable answer to your issue as the solution.

smithware's picture

Well, I've opened a support case but have yet to hear back from them.  If I receive a solution I'll post it here.

Mark Hunt 3's picture

Hello, did anyone ever get a solution for this? I am having the same problem and I am running 6.5.4.

sdo's picture

The trick is to use "prioritised" media server load balancing in the "storage unit group" that is specified in the duplication phase of the SLP policy.  Also to specify a primary/prefered "alternate read server" in the duplication phase of the SLP.

Search here:
http://www.symantec.com/business/support/knowledge_base_sli.jsp?pid=15143
...for "slp best practices".

P.S. Whilst we've mostly resolved the duplication going via LAN, they still do occassionally, especially the duplication of the NDMP images.  I haven't got to the bottom of this yet.

Mark Hunt 3's picture

Thanks for the reply. Support also sent me some information. They pointed me in the direction of the 6.5.4 Documentation Updates document - http://seer.entsupport.symantec.com/docs/318350.htm

There is a new option described on page 122 where you can chnage the default behaviour for the duplication process using the following command:

nbemmcmd -changesetting -common_server_for_dup <default|preferred|required> -machinename master server name

Select from the following options:
■ default
The default option (default) instructs NetBackup to try to match the
destination media server with the source media server. Using the default
option, NetBackup does not perform an exhaustive search for the source image.
If the media server is busy or unavailable, NetBackup uses a different media
server.
■ preferred
The preferred option instructs NetBackup to search all matching media server
selections for the source. The difference between the preferred setting and
the default setting is most evident when the source can be read from multiple
media servers, as with Shared Disk. Each media server is examined for the
source destination. And for each media server, NetBackup attempts to find
available storage units for the destination on the same media server.
If all of the storage units that match the media server are busy, NetBackup
attempts to select storage units on a different media server.
Network Optimized Backups
Network Optimized Duplication
122
■ required
The required option instructs NetBackup to search all media server selections
for the matching source. Similar to the preferred setting, NetBackup never
selects a non-common media server if there is a chance of obtaining a common
media server. For example, if the storage units on a common media server are
busy, NetBackup waits if the required setting is indicated.
Rather than fail, NetBackup allocates source and destination on different
media servers.