[OpenAFS] Vice Partition Effects on Disk I/O

chas williams chas@cmf.nrl.navy.mil
Fri, 07 Sep 2001 13:32:09 -0400

>Sun Ultra-2 running Solaris 7, uname -v = Generic_106541-14
>Fast wide differential SCSI.

i have no end of trouble with fast wide diff on suns.  what adapter
are you running and could you check sunsolve to see if there are
any patches for the adapter?  you can use prtconf to see what the
driver has negotiated as far as sync speed.  try changing the cable
as well.  any 'strange' messages appearing in /var/adm/messages?

[i have a fast wide diff raid very similar to yours.  i use the symbios
driver (glm), and i have had to throttle back the sync speed since the raids
dont seem to be able to go full 40MB/s.  i also had to find new cables
since the hp cables i had seemed to be junk.  sgi diff/wide cables seem to
be fairly high quality.]

>We could do that. I will add that the for small amounts of IO we see
>reasonable response times, when it's bursty we get slow responses.

perhaps you should try a standard benchmark on the drives?  just want
to see if its only afs with the problem.  also, run the benchmark
simultaneously on the other drives as well (after trying individual