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Netbackup: Can you restrict the number of "read" drives of a duplication job

Hi,

I have a NetBackup 7.7.3 environment with a media and master server and am using a Quantum i500 tape drive unit which has three drives dedicated to the NetBackup environment.  All of our backup and duplication jobs go directly to tape (no intervening disk backup).  The current problem I'm having is that when a duplication job kicks off the job will occupy all three drives if there is more than one tape used in the original backup job.  Ultimately, what I'd like to do is restrict the duplication process to only use two drives concurrently so that if there are any backup jobs that need to run there is a drive available (note we aren't using multiplexing so I understand that if there are multiple backup jobs they would queue up after the first started).  Is there a way to restrict the number of drives used by a duplication job?   Also, if there are two or more tapes in a backup job are they simultaneously read and then written to the duplication tape?

I looked at creating a separate storage unit for the duplications so that it is only allowed to use two drives, but this says two "write" drives which doesn't indicate whether or not that rule applies to drives used for reading.   I have a ticket open with Veritas but the engineer wasn't able to give me a straightforward answer and is researching this issue.  Any help is greatly appreciated.

 

Chris

3 Replies

Re: Netbackup: Can you restrict the number of "read" drives of a duplication job

I think you would have to restrict the output storage unit to one write drive.

Are you using SLP, or Vault, or scripts to perform the duplications?

If you have lots of backups which each require more than one copy, and with different retention levels, then are you aware that you could write two "in-line" copies of backups at the same time, and save yourself having to duplicate them later.

Re: Netbackup: Can you restrict the number of "read" drives of a duplication job

Don't know of a way directly to limit the number of read drives, but can think of some work arounds

1) Vault license for specific number of drives if vault are used. At least it has been so in the past.

2) bpduplicate with a bidfile and a destination storage unit with limited number of drives

3) SLP might be the same as 2)

 

The standard questions: Have you checked: 1) What has changed. 2) The manual 3) If there are any tech notes or VOX posts regarding the issue

Re: Netbackup: Can you restrict the number of "read" drives of a duplication job

Yes - you can.There is no one to one relation between storage unit and physical drives.

Create a new storage unit e.g. storageunitname-duplicate and set the concurrent write drives to the number you want. Point SLP's to this new storage unit.

Reads do not use storage unit selection. But you can set priority on duplication much lower than backup/restores. That should allow backup and restores to run before duplication.

The difference in priority seems to evaluated again dismounting a tape drive or not. Since dismounting a tape drives is a "expensive" in netbackup view, it require a large difference in priority in order to Netbackup to decide to dismount a drive.