I'm in the process of setting up a machine with a RAID array hanging
off an Adaptec 2940UW.  In the process, I've discovered a few weird
things, and I was wondering if anybody could comment:

* NetBSD didn't successfully probe the disks until I told SCSISelect
  (the ahc's config program) to disable "sync negotiation" on all the
  disks.  It would complain "ahc0: board not responding", or something
  very similar.

* Doing anything with the RAID array seems pretty slow.  It took over
  two hours to initialize the parity information for a RAID5 array
  across three 9G disks.  It's currently doing a 17GB newfs, and it
  looks like that will take about an hour by the time it's done.

* Trying to speed things up, I tried options AHC_TAGENABLE and
  AHC_SCBPAGING_ENABLE.  This caused the "ahc0: board not responding"
  messages to reappear.  Running with only AHC_TAGENABLE seems to work
  fine, though.  I didn't see anything in ahc(4) saying that those two
  options were dangerous, but I guess the fact that they're not
  enabled by default should tell me something, eh?

This is an i386, 1.4 system.  2940UW with 3 Fujitsu 9GB UW disks
hanging off it.  It also has an on-board ncr and pciide.

I haven't yet tried actually reading and writing files on the RAID
array, because it's not done newfs'ing.  But it may be that actual
file operations will be pretty fast.

Chris

-- 
-----------------------------------------------------cjones@math.montana.edu
Chris Jones                                          cjones@honors.montana.edu
           Mad scientist at large                    cjones@nervana.montana.edu
"Is this going to be a stand-up programming session, sir, or another bug hunt?"