I'm having some performance/thruput discrepancy problem with LTO-2 drives
and want to seek suggestions to resolve my problems.


My backup infrastructure has the following:

- Software

NBU DataCenter 4.5FP8


- NBU master+media server (running Solaris 8):

Sun Fire-280R:    PCI1 slot has Dual-Channel Ultra320 SCSI-Channel Card
                  PCI3 slot has Dual-Channel Ultra320 SCSI-Channel Card

- Tape Library:

Sun L100 w/ 3 x LTO-2 drives w/ LVD SCSI controller



And, I have the following physical SCSI connectivity:

PCI1 top channel    -> HP LTO-2 Drive2 in Sun L100 Library
PCI1 bottom channel -> HP LTO-2 Drive3 in Sun L100 Library 
PCI3 top channel    -> HP LTO-2 Drive1 in Sun L100 Library
PCI3 bottom channel -> Sun L100 Library controller

(each SCSI channel is properly terminated with an LVD SCSI terminator)



A problem that I'm having is that Drive1 runs at around 24-27MB/sec while
Drive2 at 16-17MB/sec to back up the same host at the same time (the 2
drives concurrently running).


Any recommendation for this situation? Would getting a 3rd Ultra320 SCSI
card and connecting each tape drive from a dedicated SCSI card be something
worth trying to resolve this performance discrepancy problem?


Thanks for your help in advance!


- Young