Re: kvm, drbd, elevator, rotational - quite an interesting co-operation

Lars Ellenberg
2009-07-06T09:42:35Z

On Fri, Jul 03, 2009 at 05:59:05PM -0500, Javier Guerra wrote:
> On Fri, Jul 3, 2009 at 9:00 AM, Lars Ellenberg<lars.ellenberg-63ez5xqkn6DQT0dZR+AlfA@public.gmane.org> wrote:
> > the elevator of the lower level block device (in this case,
> > the kvm virtual block device, or the host real block device)
>
> so, the original post (Michael) was running drbd on the KVM guests??

That was my impression, from the introduction:
>> Today I tried drbd for the first time, and decided to start
>> experimenting on two virtual machines.

> i thought the only sensible setup was using dbrb on the hosts, to make
> VMs live-migrable.

Right.
But his findings are still interessting. It may help to track down all
spurious timeouts and "anticipatory" idle-waits, and try to disable
them, or move them out of the picture. Even ignoring DRBD for a moment,
that should also be an interessting and beneficial excercise
for VM block device performance in virtualization alone.

--
: Lars Ellenberg
: LINBIT | Your Way to High Availability
: DRBD/HA support and consulting http://www.linbit.com

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.
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