Compression not working

[Philip87]

Hello,

I've got a problem with the compression on the tape drives.

I have a LTO Ultrium 3 tape drive with 400 GB tape cartridges. When I run the backup it stops around 300 GB and asks me for a new tape. The compression ratio is 0.799:1. So it writes more data on tape.

Is there anything I can do about this problem.

I already have the latest firmware. The driver version of the tape drive is 5.1.23.0 (5-9-2006).

Thanks in advance!

Philip

[RahulG]

1st thing to do is update the tape device drivers, Download and install the latest symantec drivers for your tape drive.

Do you have encryption enabled in the backup job ?

[Philip87]

Where can I find the latest tape device drivers? I have no encryption enabled in the backup!!

[Simon_B_]

What kind of data do you backup to tape? The compression ratio highly depends on this. If you only back up data which is already compressed (jpeg, png, movie files, mp3 for example) it is normal that the compression can not archive further data reduction but instead the compression overhead might indeed lead to compressed files that are larger then the original ones.

What happens if you run the job without compression - do you get a 1:1 ratio then?

[Philip87]

I just saw that the most files on the C: drive are compressed. I have disabled compression and I'm going to check the backup tonight.

I'll let you know the outcome tomorrow.

[RahulG]

You can search for the drivers on the following link

http://www.symantec.com/business/support/index?page=landing&key=15047

As per the version of backup exec you are running , You need to download and install the latest symantec drivers

Once you have installed the Drivers you would need to reboot your Library and the media server .

[CraigV]

...I have seen similar posts over the past year or so where data was reinflated during a backup. This would explain why your ration is under 1:1...

[Philip87]

I tested yesterday with the compression disabled. The backup did 1:1. After this I enabled the compression and I did a test backup of 10 GB, this one did 2:1 compression (I did a backup of the drive with almost all the files compressed).

I left the compression enabled and the backup overnight completed succesfully, but the compression was around 0.9:1 (I've backed up 345 GB on a 391 GB tape and I have 8 GB left on tape).

I'll check the backup again tomorrow.

[CraigV]

...have you tried swopping between software and hardware compression to see if either of them works better?