[Pkg-xen-devel] Bug#666135: Bug#666135: Multiple "Domain-0", slow libvirt

[Thomas Goirand]

Hi Dmitry,

Just to make sure everything's clear: I don't know better than you, I'm
trying to figure out clues that could lead us to understand what's going
on here.

On 04/02/2012 04:46 AM, Dmitry Ogorodnikov wrote:
> Hi Thomas,
> 
>>> I have a problem with libvirt, it works slow. For example, "virsh
>>> list" takes 6..7 seconds.
>>>
>>> I ask xen-users list with no luck. According to google, this problem
>>> is not wide spreaded, so maybe it's debian specific. If not, please
>>> hint where I should go next.
>>>
>>> I found this in libvirt log:
>>
>> Hi Dmitry,
>>
>> If you are having an issue with libvirt, why do you send a bug report
>> against the Xen hypervisor? It doesn't make sense.
> 
> Are you sure this is a libvirt issue? Exactly this libvirt works fine
> with KVM, exactly this libvirt works fine with Xen on RHEL5 servers.

Right, libvirt is actively supported by RedHat, which has dropped
support for Xen, and who doesn't care about Xen anymore. So that's not
surprising.

> libvirt slowness only a symptom.
> 
> Xenstore stores incorrect information (or you think
> /vm/00000000-0000-0000-0000-000000000000-1,
> /vm/00000000-0000-0000-0000-000000000000-2,
> /vm/00000000-0000-0000-0000-000000000000-3 is ok?), Xen creates and
> uses incorrect information. Bad libvirt, isn't it?

Well, sure that doesn't look a correct UUID. But by what mechanism has
these been created?

> I already do. Also I try to read xenstoed documentation, but cannot
> find something corresponding.
> So, while undocumented this is not a feature, this is a bug.

Are you saying that anything not documented is a bug?!? Gosh, there
would be so many bugs in so many software then!

> Forget libvirt, I can remove it for you, is multiple
> "/vm/00000000-0000-0000-0000-000000000000-*" entries OK?

I don't *think* it is, I don't know libvirt enough to tell. But maybe
it's using wrongly the Xen libraries, which creates these. How can you
tell for sure that this is an issue in Xen itself? Did you ask in the
xen-devel list?

> How can I remove it permanently, any useful idea?

Have you tried xenstore-rm?

Thomas