Sun StorEdge T300 on Linux RHEL AS3

We've got a T300 attached to a RHEL Advance Server box and, honestly,
the performance is horrible. (not sure if this is the right group for
this.. I apologize in advance if it is not)

For example, our internal drives (sda-sdc) blow away access to the T300
(sdd-sde):
/dev/sda:
Timing buffered disk reads: 228 MB in 3.00 seconds = 76.00 MB/sec
/dev/sdb:
Timing buffered disk reads: 172 MB in 3.00 seconds = 57.33 MB/sec
/dev/sdc:
Timing buffered disk reads: 200 MB in 3.01 seconds = 66.45 MB/sec
/dev/sdd:
Timing buffered disk reads: 12 MB in 3.15 seconds = 3.81 MB/sec
/dev/sde:
Timing buffered disk reads: 12 MB in 3.42 seconds = 3.51 MB/sec

This is a rather basic question, but how can we (I) tweak the
performance parameters on the SCSI drives? hdparm is primarily for IDE
drives.. is there something similar for SCSI drives?

Thanks!
-Rich