I am still struggling with the performance of an Adaptec 2120S RAID
controller (aac0). When testing with bonnie++ (from pkgsrc), write
performance is only around 4M/sec. The number of xfers/second, as shown
by `systat vmstat', is only around 60 while it is writing and only
around 100 when reading. This is surprisingly low.

However, when I test with a benchmark called RawIO (see
http://www.acnc.com/benchmarks.html) on the (unused) raw swap partition,
I get much better results. Sequential writing is around 35M/sec, and the
number of xfers/sec is over 1000, peaking at some 1900.

So it's not like the card is not capable of proper transfer counts and
speeds, it seems it is held back somehow by the file system or buffer
cache.

I tried tests both with a GENERIC -current kernel and the 1.6.1 release
(GENERIC and customised), and there is no significant difference. It is
the second server box I'm trying the card in, and there was no
improvement in the change.

Any ideas?

-Olaf.
-- 
___ Olaf 'Rhialto' Seibert - rhialto@       -- "What good is a Ring of Power
\X/ polderland.nl            -- if you're unable...to Speak." - Agent Elrond