Re: [Vserver] I/O CFQ scheduler

i am getting ready to upgrade the kernel from 2.6.19-vs2.2.0-rc2 (vanilla
kernel) to the current gentoo vserver-sources (2.6.20-vs2.2.0-gentoo) in our
production machine and was thinking of using the CFQ scheduler.

in an earlier msg about cfq someone mentioned this:

>Compile CFQ I/O scheduler support into the kernel and append the
>following parameter to your kernel boot parameters:
>elevator=cfq

what is elevator and how does it relate? is it something i should do?

or maybe use deadline instead?

is it worth it on a moderately loaded machine?

it is currently running 41 guests: 9 reasonably busy web servers, a *very*
busy email server and also a busy radius server. the rest are lower usage.

primary host os and most guests are gentoo-amd64 however all of the web
servers are centos4/x86_64 which chews up *considerably* more resources
(because a registered package we use requires this os for now). my primary
concern is if a cfq scheduler change from anticipatory would break any disk
configs using software raid, lvm2 and user quotas which work perfectly in our
guests.

during development and implementation of this production server i opted for
safety with the anticipatory scheduler but now that it has proven itself, i
feel the need to 'optimize' it a bit.

suggestions?

> On Tue, Jan 24, 2006 at 08:06:38PM +0300, Vasily Tarasov wrote:
> > Hello.
> >
> > Can you tell me, please, can util-vserver-0.30.209
> > <http://www.13thfloor.at/vserver/d_rel26/v2.1.0/util-vserver-0.30.209.tar>
> > work with I/O CFQ Scheduler already?
>
> yes, it's a 'hard-coded' kernel feature of the devel branch
> (for now)
>
> > How?
>
> just enable the cfq i/o scheduler for your system/tasks
> and the accounting will be done per context (guest)
>
> in the future I guess there will be util support to fine
> tune the priorities and set the I/O groups ...
>
> HTH,
> Herbert
>
> >
> > Thank you.
> > _______________________________________________
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> > Vserver@list.linux-vserver.org
> > http://list.linux-vserver.org/mailman/listinfo/vserver
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-- 
Chuck
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