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Tape capacity difference

Updated: 24 Jan 2012 | 6 comments
Amaan's picture
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This issue has been solved. See solution.

Hi, I have a question. My question is from attached screenshot:

All tapes are same tapes and we have only one tape drive but they are becoming full in different size. One is 522778560, another one is 863286528 and third one is even more 1567017472. Why they are becoming full in different points?

Sorry if this question is ever been answered before.

Thanks!

Comments

Marianne van den Berg's picture
24
Jan
2012
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Different types of data

Different types of data compress differently - some good, giving your more data written on tapes. Some data does not compress well or allow no compression at all, giving you less data on tape.

Always use uncompressed capacity for planning purposes. Anything above that is a bonus!

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

Amaan's picture
24
Jan
2012
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We are not doing any

We are not doing any compression while doing a backup.

J.Hinchcliffe's picture
24
Jan
2012
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Really?

most people have hardware compression on the tape drives by default.

I don't have to know how to spell....I work on Unix.
NetBackup 7.0.1 - AIX & Windows

Amaan's picture
24
Jan
2012
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How i can find if it is

How i can find if it is exists? How do i know if the compression is enabled in the drive.

and i told that we are not doing compression from NB end.

wr's picture
24
Jan
2012
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Compression is built-in

The LTO specification describes a Data Compression method LTO-DC, also called Streaming Lossless Data Compression (SLDC).

http://en.wikipedia.org/wiki/Linear_Tape-Open#Compression

good Will backing-up

Amaan's picture
24
Jan
2012
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Thanks so much for all. My

Thanks so much for all. My question has been answered and i am marking Mariannes answer as a solution.