Backup slowing down over time

[Jens Danstrup]

Hi
We have a Netware 6.5 Server, running on a ProLiant ML370 G4 computer, with a Storageworks Ultrium 215 internal tapestation.
For backup we use Veritas Backup Exec ver. 9.1
We run full backup every night, when there is no users logged into the server.

During the last 2 weeks the back is slowing down.
6. of january throughput = 855 Meg / minut
14. of january throughput = 738 Meg / minut

In the same period the total amount af data went up from 102.5 Gb to 103.8 Gb.

There have been no changes to either hardware or software in the period.

Can anyone tell me what is going wrong ?