Backup Exec 8.6 Slow, backing up local files

[romahan]

I'm using Backup Exec 8.6 on a Win2003 member server (Compaq DL380). We have a Compaq MSL5026 library with SDLT 110/220 drives. The library and tapes are on their own SCSI controller. One tape drive shares one channel with the library. When I backup some of the files on the local server I get inconsistent speeds. This can happen on either drive. I may get 300 to 700 MB/min on one backup then I will get 180 MB/min the next time on the same data. When I get these slow speeds the Verify is also slow (usually the same rate). I have similar issues with network backups but the local backups are puzzling. I have tried many things including upping the buffer size on the drives to 1024 (this seemed to help backup speeds overall but it didn’t cure the very slow backup). I also defragged the local server. Any ideas?