LTO 1 Tape Drive reduction in backup Size

[Clarke_Hotton]

We have been successfully getting 127-128GB of data onto our LTO1 (100GB Capacity uncompressed) Tapes for the last year. It has been with a mixture of Software compression and Tape Drive compression.
A week ago, the Backup of the Mailboxes went into the next day, so I cancelled the job. I defragged the Database and recovered about 2GB of data from the Defrag, now the Mailbox backup is good, however the tapes max out at between 103 and 107GB before they are requesting a new tape.
Can anyone shed any light on why this may have been. It is a design company with the majority of data being PDF's and Jpg's so the compression on them is minimal anyway. I have not made any changes to the Compression values in Veritas, or turned off COmpression on the Tape Drive. we have also rebooted the server and restarted the BE services several times to see if that helps.
I just find it unusual that we were getting 128GB on a tape, now we only get 103-107GB.

Anyone have any suggestions.

[shweta_rege]

Hello,


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





Thank You,


Shweta

[Clarke_Hotton]

Thank you for your response
However it was not what I was after.
I am well aware of the Compression issue, in fact I actually mentioned it in the original post. My concern is the sudden drop capacity of the Tapes, and it is all tapes.