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fragment size

Created: 11 Oct 2012 • Updated: 11 Dec 2012 | 6 comments
This issue has been solved. See solution.

To reduce the effect of multiplexing on restore times, set the storage unit maximum fragment size to a value smaller than the largest allowed value. Also, enable fast-tape positioning (locate block), if it applies to the tape drives in use.

What this fragment size do?

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Nathan Kippen's picture

See this technote:

http://www.symantec.com/business/support/index?pag...

Also see this thread:

https://www-secure.symantec.com/connect/forums/how...

Symantec Certified Specialist
(NBU 7.5.0.6)
Don't forget to vote or mark solution!

SOLUTION
Marianne's picture

Keep on reading....

Read this topic in Admin Guide I: Reduce fragment size storage unit setting.

Read the explanation in Table 11-5.

Do a test backup with default fragment size directly to tape. It must be a large backup with lots of files (File server folders will be ideal.)

After you have read this, go apply on your Storage Units. (Some people prefer a value of 2000, but we also see good results with 5000.)
Rerun the same test backup.

Then perform a test restore (one file to a temp folder) from the backup that was done before the change.

Then perform a test restore from the backup after the change.

Please tell us the result.

PS: Do you know Arun K and NIKHIL2346565959?

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

Andy2345's picture

No.I dont know them.

I have done the restore.One is fast and one is slow.

So on tape we have tape marks which is called fragment size?

Marianne's picture

Excellent! You have figured it out!

This is how all of us learn.
Sometimes we read something in the manual that we don't fully understand.
We then go an test it on live or test environment. 
When we see the results, we understand the theory in the manual.

The type of questions you ask are similar to those of NIKHIL and Arun.....

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

Andy2345's picture

Thanks.But i waana know what exactly a tape has?

It has tar files?

Marianne's picture

How is this question related to your opening post? If you "waana" know about NBU backup format, there is MORE information in NBU manuals and on Symantec Support site.

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