Feedback solicited - read performance is awful with PE2650 runningRH AS

Gary Mansell Gary.Mansell at ricardo.com
Tue Oct 21 06:22:00 CDT 2003


I would really appreciate some help from the list here to see if anyone
else is suffering from the same problem that I am. I appear to have
fallen foul of a problem with RH AS products running on Dell PE2650's.

I have raised bug number #106771 at http://bugzilla.redhat.com and I
have tried to raise the issue with Dell but I am not getting very far -
both parties blame the other and I am stuck in the middle getting
nowhere.

I have installed RH AS 2.1 and RH AS 3.0b2 and have found that the read
performance from the system mirror is awful - it is less than the write
speed!! If I install RH 9.0 or RH 7.3 the read performance to this same
device is fine.

Please could anyone who has a Dell PE2650 with a version of RH AS
installed run the following quick and dirty (but representative) disk
performance tests and let me know if they find the same.

Write Performance:
/usr/bin/time dd if=/dev/zero of=/testfile bs=16384 count=250000

Read Performance:
/usr/bin/time dd if=/testfile of=/dev/null bs=16384


FYI, I have a Dell PE2650 with 2x 2.4GHz Zeons (Hyperthreading enabled),
2GB RAM, 2x18GB internal system disks in a HW mirror configuration using
the Adaptec PERC 3Di.

Thanks in advance

-- 

Gary Mansell
Technical Computing Team Leader
IT Department

Ricardo Consulting Engineers Ltd.
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