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Tape Library Best Practices

Created: 02 Jul 2013 • Updated: 07 Aug 2013 | 4 comments
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Inherited a NBU 7.1 environment running on an old Sun box with an SL48 robot / four drive library.  Looking to upgrade soon to a new server running RHEL 6.3 and NBU 7.5 with a new LTO 5 four drive library.  Backups seem to run but, although the storage unit is configured with max concurrent write drives = 4 and max streams per drive = 8, multiple simultaneously running jobs write to a single drive, leaving the other three idle.  Understand that a job may not be able to write to two drives simultaneously (maybe someone can confirm this).  Policy Storage is set to Any_Available.

Part 2.  I have a mix of Windows and Linux application, file, and database servers and need to shrink my backup times.  What are some thoughts regarding four individual tape drives versus a four-drive library?  I've run HP DP with individual drives and have had no problem running single jobs to multiple drives.

Operating Systems:

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Yasuhisa Ishikawa's picture

When MPX is enabled, NetBackup allocate active tape drive with free MPX capacity rather than idle drives. It is not possible to allocate idle drives for jobs its maximum MPX is grater than 1.

I highly recommend you not to use standalone tape drives. NetBackup always append data behind the last unexpired backup image. NetBackup has no option to overwrite tapes without manual intervention. This means you have to change tapes before NB run out tape capacity. With tape library, you don't have to unload/load tapes manually.

Authorized Symantec Consultant(ASC) Data Protection in Tokyo, Japan

Marianne's picture

MPX of 8 seems very high. We prefer to set this value to 4.

To see how drives are assigned to jobs, have a look at this topic in NBU Admin Guide I:

About multiplexing
Example of using multiplexing with schedules

I agree with Yasuhisa - managing standalone tape drives in NBU is a nightmare.

You may want to consider Shared Storage Option where tape drives are SAN attached and zoned to multiple media servers.

This way you will be able to install Media server software on your large database servers so that they can backup directly to san attached tape instead of over the network to a media server, normally cutting down backup time considerably.
This option requires the master server to have Enterprise Server license.
The clients that are installed with media server software will need Enterprise Client license. We call these client San Media Servers.
Shared Storage Option license is needed for each shared drive.

Hope this helps.

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

LSchumacher's picture

We do have the enterprise version and we have about 6TB of Clustered SAN data that we are looking to backup to another SAN.  Then we plan to backup our other databases and VM snapshots there as well.  From that SAN we plan to backup to tape.

Last question.  Some of the folders on the clustered SAN are in excess og 500GB.  I have the policy selections set as individual folders like this:


The policy is set to allow multiple streams, but the folders with 500+ MB are taking 25+ hours.  Is there any way to tweak this policy to reduce that window?

Marianne's picture

Two possibilities: 

FlashBackup - raw device is backed up with ability to restore individual files.

Break down the folders even further, e.g. 


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