We have a machine with an Adaptec 2940UW Ultra-Wide SCSI card attached to a
Streamlogic Ultra-wide RAID unit, running SCO OpenServer Enterprise 5.0.2
with SMP. Everything has been set to Ultra-wide 40MB/s speeds.
We've been getting complaints about disk access speed, and when we analysed
the throughput using sar -d, it appears that we're only getting a 1mb per
second throughput - disk busy 100% of the time, average blocks per second
around 2000. On an Ultra Wide SCSI BUS with the capability of 40MB per
second, this seems dire. OK, the RAID will probably slow things down, but it
should still be higher than this.
Can anyone suggest why this should be, or suggest any tuning improvements to
the kernel to help with this ??