Performance degrade

Hi,

Master server : windows 2008

Media server : Window 2008

Netbackup version on both Master and Media is : 7.1.0.3

Clients: AIX 6.1 TL7

We are taking sap and Oracle backup and storage is DD890.

for last 3 days the backups are writing very slow, please let me what could be the reason and also let me know what need to be checked.

for eg if usaully backup writes 30000 kB/s now its writes to 15000 KB/s and that takes double the amount of time to get complete.

Thanks

-Chan