kvm locks up when out of disk space

[Michal Suchanek]

Running a VM using raw sparse disk image on kvm 0.14 on Debian.

When disk writes use up all disk space kvm locks up.

if it cannot handle this situation gracefully (eg suspend the VM until space becomes available) it should at the very least report an error and exit, not keep sitting there.

[Michael Tokarev (mjt+launchpad-tls)]

I already replied to the OP in the Debian bug tracking system, and closed his bug there, see http://bugs.debian.org/628152 .

[Stefan Hajnoczi (stefanha)]

On Sun, May 29, 2011 at 11:48 AM, Michal Suchanek <email address hidden> wrote:
> Public bug reported:
>
> Running a VM using raw sparse disk image on kvm 0.14 on Debian.
>
> When disk writes use up all disk space kvm locks up.
>
> if it cannot handle this situation gracefully (eg suspend the VM until
> space becomes available) it should at the very least report an error and
> exit, not keep sitting there.

Actually it should pause the VM - are you sure that KVM is "locking
up"? If you run with SDL the window title says "[Stopped]" and you
can resume the VM with the "c" (continue) QEMU monitor command once
you've rectified the storage shortage.

Are you using libvirt (virsh/virt-manager)?

What makes you think that KVM is locked up?

How much CPU is the qemu-kvm process consuming?

Stefan

[Michal Suchanek (hramrach)]

On 29 May 2011 13:33, Stefan Hajnoczi <email address hidden> wrote:
> On Sun, May 29, 2011 at 11:48 AM, Michal Suchanek <email address hidden> wrote:
>> Public bug reported:
>>
>> Running a VM using raw sparse disk image on kvm 0.14 on Debian.
>>
>> When disk writes use up all disk space kvm locks up.
>>
>> if it cannot handle this situation gracefully (eg suspend the VM until
>> space becomes available) it should at the very least report an error and
>> exit, not keep sitting there.
>
> Actually it should pause the VM - are you sure that KVM is "locking
> up"?  If you run with SDL the window title says "[Stopped]" and you

Unfortunately, the window title is not visible at all times so even if
it says [Stopped] it is not useful indication of the VM state.

> can resume the VM with the "c" (continue) QEMU monitor command once
> you've rectified the storage shortage.
>
> Are you using libvirt (virsh/virt-manager)?

No.

>
> What makes you think that KVM is locked up?

Nothing apparent happens. eg. the VM mouse cursor does not move, no
messages printed in the terminal from which kvm was started.

>
> How much CPU is the qemu-kvm process consuming?

Did not check.

Thanks

Michal