Re: kvm + raid1 showstopper bug

Stefan Hajnoczi
2012-02-17T11:30:18Z

On Fri, Feb 17, 2012 at 4:57 AM, Pete Ashdown <pashdown@xmission.com> wrote:
> I've been waiting for some response from the Ubuntu team regarding a bug on
> launchpad, but it appears that it isn't being taken seriously:
>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/745785

This looks interesting. Let me try to summarize, please point out if
I get something wrong:

You have software RAID1 on the host, your disk images live on this
device. Whenever checkarray runs on the host you find that VMs become
unresponsive. Guests print warnings that a task is blocked for more
than 120 seconds. Guests become unresponsive on the network.

The fact that the QEMU monitor and VNC still work mean that QEMU is
not probably still running the VM. I think the guest kernel is upset,
perhaps QEMU needs to do something to help these I/Os along.

Please post your qemu-kvm command-line or libvirt domain XML.

What's the easiest way to reproduce this?

Stefan