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Tape to tape duplication - Less data size

Created: 09 Sep 2013 • Updated: 10 Sep 2013 | 4 comments
This issue has been solved. See solution.

Hi all,

We performed tape to tape duplication for one of our client...

When we compared the size of the data, it was less from the original copy from where it was duplicated.

I have attached the screenshot for the reference... In the attachment the first one is the new tape to which the data was duplicated ( Around 630GB)

Note: There is no other data stored in the second tape.

Please let me know the reason.

Thanks

Operating Systems:

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revaroo's picture

One was MPX'ed the other was not, therefore more use of blocks on the MPX'ed tape.

SOLUTION
cs3472's picture

Thanks revaroo...

But when we expired the backup id's in the second tape through GUI, the data size is still seen in the available_media command. Is it normal or is there anything else to be done to make it reusuable?

Thanks in advance...

revaroo's picture

Perfectly normal, see Mariannes post below for the explanation

Marianne's picture

is there anything else to be done to make it reusuable?

ALL images need to expire to make a tape reusable.

See this excellent blog: https://www-secure.symantec.com/connect/blogs/understanding-how-netbackup-writes-tape

You can use 'Images on media' report (or bpimmedia from cmd) to compare images on the 2 tapes.

 

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