Author: Clemens Koller Date: To: Matt CC: exim-users Subject: Re: [exim] Speeding Up Exim
Matt schrieb: >>> I wander if the SATA feature of NCQ would speed the disk I/O up but
>>> there is likely no easy way to upgrade CentOS 4.x to do that.
>> AFAICT CentOS 4.5 kernel was originally based on 2.6.9. A long time
>> has passed since then and the 2.6.21/2.6.22 kernels where the new
>> libata based disk subsystem (starting with the nice features you are
>> looking for) was first included in the kernel.
>>
>> The upgrade should still be doable (depending on your skills).
>>
>> The most significant change you might experience is the new udev
>> device structure which replaced devfs at around ~2.6.12 IIRC.
>> Anyway. I'd give it a shot if you have some minutes of downtime.
>> Well, if you update... go to the latest stable tree.
>
> This is what I show.
>
> Linux version 2.6.9-67.0.4.ELsmp (mockbuild@???) (gcc
> version 3.4.6 20060404 (Red Hat 3.4.6-9)) #1 SMP Sun Feb 3 07:08:57
> EST 2008
>
> Also,
>
> libata version 2.00 loaded.
> [.....]
Well, check the kernel mailing list or the linux-ide list for
details about the status of the NCQ support. Some time ago, somebody
posted some interesting numbers about NCQ boosting performance.
It's still the question if this also helps in case of exim's workload.
And regarding kernel upgrades:
Just compile and boot a new kernel, leaving the old header files
untouched should give you a rought estimate about your mileage.
"backporting" is IMHO the wrong term here... just install them
side by side.
Well... I'm coming from the LFS world without any distribution
specific bells'n'whistles.
