Backup sizing isssues

I do not have model # of the backup drive but it can handle a 40 GB backup tape. We use 20/40 backup tapes in a dds-4 drive. We use Server 2K3 and the Windows Backup utility to backup our data. However once it gets to 20GB it stops backing up. is there and way to get the drive or the backup utility to use the other 20 GB of space on the tape?

Thanks

 

I don't think Windows Backup utility will compress.
40 GB is the compressed size.

If your backing up critical stuff like Exchange or SQL do not use the Windows Backup Utility.

Veritas

 

right, so how do i get it to use the 40GB?

 

The capacity of the tape is 20 gig not 40.
It will take 40 gig of data and compress it to 20 but it will not hold 40.
Make sence?

 

So when the log says it backed up 20 GB it is not refering to the amount of data on the disk, just how much space on the tape is being used?