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Data Catridge 72 - Data Storage Issue

 
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Occasional Visitor

Data Catridge 72 - Data Storage Issue

Hi All,

 

   I am using HP DAT 72 Data catridge for storing SQL database. The database is already compressed while backuping up using a 3rd party tool and after that I use NTBACKUP to write the compressed database to the tape. Each database will be of the size 10GB after compression. The tape is of 72GB and I am able to write only 3 database files to the tape which will be 30GB in total (3 * 10GB). When I try to write the 4th file to the tape it shows the message that there is no enough disk space. When there is around 42GB free space after 30GB is written why this message is shown?

 

Can anyone help of this? Why I am not able to write data to the remaining space in the tape? I have attached the screen shot of the message.

 

Thanks in Advance

Rajeev

2 REPLIES 2
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Respected Contributor

Re: Data Catridge 72 - Data Storage Issue

The problem lies in the way the tape manufacturers label or name the tapes.
A DAT72 tape will actually only hold 36GB of data natively and 'upto' 72GB when compresses at 2:1.
Its the same with all tapes, ie a DAT40 is only actually a 20GB tape.
In reality nobody normally gets 2:1 compression, if you do, you're doing well!


If you are getting, say 1.2:1 then the max you'll fit on your tape is only 43GB NOT 72GB.

You say the data you are backing up is already compressed, therefore NT Backup will probably not be able to compress it any further so you'll probably be limited to the native 36GB on your tapes.

 


Thanks,

Mark...

 


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Advisor

Re: Data Catridge 72 - Data Storage Issue

I feel your pain.  I have a client that has a DAT 72.  Lately the max he can backup on one tape is 32gb.  Right now I have another client that can only backup about 100gb on a dat160.  Updating the firmware and using tape tools to test it usually did not make a difference.

 

This stinks.. doesn't it?