ML 350 g5 RHEL4u3 E200i IOWAIT / slow IO

[jan terje tonnessen]

Have an ML 350 G5 with E200i controller upgraded with the SA641/642 BBWC enabler (351580-B21).
3 SATA disks (2 in RAID1 +1 spare disk).
RHEL 4 update 3.
Latest drivers according to HP web pages:
Smart Array E200 Controller Firmware Version 1.20
Smart Array Controller (x86/AMD32) Driver cpq_cciss-2.6.12-6.rhel4.i686.rpm

Unpacking a 3GB tar-file takes 6 min 20 sec, while it takes approx 2 minutes on my old PC.

Can anybody help me with the poor IO performance ?

[jan terje tonnessen]

Looks as if this problem can be the same as another thread on this forum:
"SAS Performance reduced almost 800%"
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=1065800

I'll try to modify the settings in /sys/block/cciss!c0d0/queue/read_ahead_kb
and see if it helps....