Tape won't compress data

[Jamie_Barmach]

I have a client that has a tape drive with a capacity of 20/40. I have compression enabled, but the tape fills up at 25GB. Any suggestions would be greatly appreciated.

[Amruta_Bhide]

Hello,
Are you using Hardware or Software compression?

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Hardware compression is done by the device itself. When you use hardware compression option on Backup Exec (BE), BE commands the hardware to go ahead with the compression. However the hardware compression depends on the device. The device should support Hardware Compression. We advice you to contact your Vendor for more information of the same.

Software compression is done by BE. It is said to achivachievepression of 2:1 but that ratio is hardly ever achieved. Compression can be highly variable depending on your input data, as the software compression depends on the type of file or data you are trying to back up. For example: Already compressed files cannot be compressed any further. And the compression for normal '.ttext files will be more than the compression of '.gif' or database files.


You can refer to the following article to understand this concept better.



http://seer.support.veritas.com/docs/199542.htm

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You can also go through the following article which will help to check that the data is being properly written to the media.




http://seer.support.veritas.com/docs/246958.htm


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Thanks.

[Ken_Putnam]

If you are getting 25 GB on a 20/40 tape compression IS working, and you are getting approx 1.25:1

I use 1.3:1 a a rule of thumb, so you are right in the ball partk. Remember that 2:1 compression is marketing fantasy not engineering promise. See http://seer.support.veritas.com/docs/199542.htmMessage was edited by:
Ken Putnam

[shweta_rege]

Hello,

Did the solution provided to you by Amruta help you

Kindly update us on the issue

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Note : If we do not receive your reply within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.


Thank You