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NetBackup 7.1 - Windows Slow duplication Tape to Tape

Posted by tanders1 
NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 21, 2015 10:35AM
Hello,

I have been pulling my hair out for a couple of weeks on this issue. I first backup to tape and that is multiplexing so lots of jobs run at the same time. Then, I start duplication from the current tapes to new tapes. For some of the server images, it goes pretty quickly and I can actually watch the file size go up as it duplicates. Then, there are server images that take forever, sometimes over two days where there can be five minutes that go by with no progress at all made with the duplication. What could be wrong? What can I look at to debug this issue? Thanks in advance for your expertise.

-Tom
NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 21, 2015 11:12AM
First make sure your data buffers are set. This can improve performance

InstallPathVeritasNetBackupdbconfig

(touch files are plain text files no extensions)
NUMBER_DATA_BUFFERS
NUMBER_DATA_BUFFERS_RESTORE

This can be a trial and error kind of thing but we use LOT3-5 and we have the data buffers set to 256.

2nd thing consider not duplicating from tape. They can only do one thing at a time and can end up searching for data sequentially. Consider basic disk and staging, or synthetic backup, or deduplication in combination with data life cycle policies.

NBU 7.1 is fairly old I also suggest upgrading to the latest release to avoid possible bugs in the software.
NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 29, 2015 03:04AM
[quote]I first backup to tape and that is multiplexing so lots of jobs run at the same time. Then, I start duplication from the current tapes to new tapes. For some of the server images, it goes pretty quickly and I can actually watch the file size go up as it duplicates.
[/quote]
Are you specifying -mpx on your bpduplicate? If you don't, the backups
will be "de-multiplexed" on the copies, which mean it will have to go
through the original tapes several times to pick out each backup image
individually. If you use -mpx, it'll grab all the backup images in one
pass and leave them multiplexed on the copies.

- Bluejay Adametz

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- Burt Goldman

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NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 29, 2015 04:29AM
-- How do I check for the -mpx on my bpduplicate? The entire job is run through a GUI interface so I have never seen that option.

I first backup to tape and that is multiplexing so lots of jobs run at the same time. Then, I start duplication from the current tapes to new tapes. For some of the server images, it goes pretty quickly and I can actually watch the file size go up as it duplicates.

Are you specifying -mpx on your bpduplicate? If you don't, the backups
will be "de-multiplexed" on the copies, which mean it will have to go
through the original tapes several times to pick out each backup image
individually. If you use -mpx, it'll grab all the backup images in one
pass and leave them multiplexed on the copies.
NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 29, 2015 04:37AM
[quote]-- How do I check for the -mpx on my bpduplicate? The entire job is run through a GUI interface so I have never seen that option.
[/quote]
I've only done duplications via the command line (we script our
duplications), However, looking around in the Java GUI, when you get
to the "Setup Duplication Variables" screen and set the destination of
the copy, there's a checkbox near the bottom that says "Preserve
multiplexing".

- Bluejay Adametz

Notice is hereby given that all notices to be given with regards
to further notices will be notified in a notice to be notified
in our next notice.

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NOTICE: This message, including any attachments, is only for the use of the
intended recipient(s) and may contain confidential and privileged
information, or information otherwise protected from disclosure by law. If
the reader of this message is not the intended recipient, you are hereby
notified that any use, disclosure, copying, dissemination or distribution
of this message or any of its attachments is strictly prohibited. If you
received this message in error, please contact the sender immediately by
reply email and destroy this message, including all attachments, and any
copies thereof.
_______________________________________________
Veritas-bu maillist - Veritas-bu < at > mailman.eng.auburn.edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
NetBackup 7.1 - Windows Slow duplication Tape to Tape
January 29, 2015 10:41AM
[quote] 2nd thing consider not duplicating from tape. They can only do one thing at a time and can end up searching for data sequentially. Consider basic disk and staging, or synthetic backup, or deduplication in combination with data life cycle policies.

[/quote]
BasicDisk is free, and can make use of cheap local disk attached to the backup server. If you have a few 3.5" drive slots, filling them with large disks and doing a RAID0 or a concatenation with windows software raid will give you a lot of space to work with. unprotected space is probably OK, if you lose the disk you only lose the current backups that haven't been spooled to tape yet. (of course, your business requirements may vary)

Since you're doing lots of simultaneous backups, 7200rpm disks are going to do a lot better than 5400.

BasicDisk is also easy to set up. If you don't have the money for the better solutions, It's totally the way to go instead of multiplexing. Create a new "storage unit" under netbackup management -> storage -> storage units. There's a check box for "staging", it will automatically back up to the disk volume you give it, then spool things off to tape when the disk backup is done. It took me a few hours to get it all working, including reading a few docs.
--
Dan Pritts
ICPSR Computing & Network Services
University of Michigan
+1 (734)615-7362
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