DLT 35/70 DLT Library slow performance

[Ayman Altounji]

We upgraded from Windows NT4 to Windows 2000 and the performance of the library drop from 200MB/min to 80-100Mb/min. The machine has the latest firmware and drivers from Compaq. The backup software is Veritas Backup Exec 8.6. The backup software reports 80Mb/min on backup and yet 390Mb/min on the verify phase.

The library has two drives (device 5 & 6) and the robot (device 4) connected to a 64bit/66 Ultra3 SCSI card. The server is a proliant 1850R (Pentium 400).

The device setting on the backup software are 64K blocks, 1024K buffer, 10 buffers count, and high water count 0.

Any ideas on what could be causing this slow down? What would be the expected througput for this DLT library in Windows 2000?