> First off, it was _vital_ that write-back-cache was enabled
> on the SCSI disks.  Turning it on made a _huge_ difference in the write
> performance.

You know this risks data loss if you have a power outage?  Worst case
is that filesystem meta data updates are re-ordered and/or lost, and
fsck may not be able to repair the damage.  Not likely, but possible.

You're in good company of course -- most (all?) IDE disks ship with
write back cache enabled.  PC hardware "engineering" ... sigh. :-(

Regards,

Giles