Feedback solicited - read performance is awful with PE2650 runningRH AS

jason andrade jason at
Tue Oct 21 07:16:00 CDT 2003

On Tue, 21 Oct 2003, Gary Mansell wrote:

> 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.

hi gary,

i don't have the specific config you have above but i do have a Dell PE2500
with the perc3/di and RH 2.1/ES installed.  AFAIK there is little or no
difference between AS/ES apart from the clustering stuff.  I don't see
this problem - read performance is faster than write and both are acceptable
(for a PERC3/Di anyway).

> 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.

a quick check - got the latest system bios and perc firmware on this machine ?
(and tried turning off HT, just for laughs?)

do you have cache enabled on your mirrored container ? e.g

container set cache <#> /read_cache_enable /write_cache_enable

of course i am not sure if this makes any difference at all (can someone else
comment?) as i don't understand what the documentation says: "Useful only if a
native operating system's file system resides on this container".

from what i can tell this means this only works if running NTFS ?



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