What is expected performance from H/W RAID 5?

[Matthew Clark]

What would be a decent write performance from a SCSI H/W RAID array?

We have 5 x Ultra Wide 9Gb 10000RPM SCSI Disks (So supposedly 40MB per SCSI
channel?) 4 of which are ONLINE with 1 Hot Spare..(RAID 5, 26Gb Logical
drive, MegaRAID controller, Single PIII 500 Xeon processor)

Now I would expect at least 15+ MB/sec from this array (Bonnie, Write Chars)
as I get around 8MB per sec from a single IDE drive..

Theoretically, it should be 20+ MB/sec shouldn't it?

Regards,

Matthew Clark.