Hardware

Hello all !

I have Solaris 9 4/03 kernel patch 112233-05 on SunFire4800 server with
Symmetrix disk array attached. Now I do some IO tests on the Symmetrix disk
taken as it is without Veritas VM. And I see some interesting results with
the following parameters:

maxphys = 8388608, sd_max_xfer_size = 8388608, maxcontig = 256.

Doing "dd if=/dev/zero of= /some_device bs=8192k count=1000" I have found out
, that:

1) with sd_max_xfer_size = 8MB 8MB writes were performed on the Symmetrix
raw device even when maxphys was set equal to 1MB (!);

2) newfs -C 128 couldn't change maxcontig size (while maxphys was =
8388608 ) from default value (64), only tunefs -a could really do it;

3) setting maxcontig > 128 during test execution on file system couldn't
rise IO-size more than 800k (ufs_HW is larger than 1 MB);

4) doing serial writes on file system resulted in better performance even
with smaller IO-size than on the raw device. (Because of more IO-requests in
parallel?)

Please, could anybody comment all that? Regards, Pavel

P.S. I have upgraded the OS up to 112233-07 kernel patch level and set ufs:ufs_WRITES = 0.
Just the same! No more than 800k per write request.