Re: [Xen-users] Xen system hang or freeze
You and Nick both see this problem on a system with eight cores.
You have 4 domUs, Nick has 3 domUs.
I think a reasonable hypothesis is that this is some kind of resource
Some questions that might help see how similar your scenario and
1. How many vcpus does each of your domUs have?
2. Do you define pinning, cap or weight for your domUs?
3. Does sar on the guests show a high %steal before the problem
4. Do you limit the number of vcpus that Dom0 has? If not, I would
suggest that you try this an dsee if the problem occurs when you know
that there should be free vcpus for each of your domUs.
Do you limit your Dom0
On May 5, 2009, at 2:42 AM, Martin Fernau wrote:
did you find out anything helpful about this problem?
I just had this freeze this morning again. Server freezed and no
working any more. After 5 weeks of normal running. It seems that
this is my
intervall of this problem.
I really appreciated anything helpful about this! I'm totally stuck
Am Freitag, 24. April 2009 schrieb Nick Anderson:
On Thu, Apr 23, 2009 at 10:01:02PM -0400, Peter Booth wrote:
When you got the "soft lockup" errors were they always with CPU0?
Yes I believe so. But since I updated to the latest debian patched
kernel I havent seen that soft lockup error.
Do you have any nesting in your LVM definitions?
Is dom0 making use of LVM?
No it is not.
Does the host have a wireless card?
What graphics card does it have?
Just the onboard graphics 01:05.0 VGA compatible controller: ATI
Technologies Inc ES1000 (rev 02)
There is a Xen 2.6.18 kernel bug that might be related to what you
as well as a patch:
Yes I think that patch is in the latest kernel update which made the
soft lockup messages go away. Odly everyone else that noted the soft
lockup errors only noted them as an annoyance. I don't recall ever
seeing anyone link the messages with any actual undesirable behavior
outside of the msgs themselves.
I appreciate that this freezing occurs when the system is quiet,
seems as if the hypervisor CPU scheduler might play some part in
such that the guest vcpus don't get scheduled on a pcpu. If it
were me I
would try limiting dom0 to four vcpus - not as a long-term
configuration, but to see whether the problem recurred when we
each domU should have an available CPU.
I was considering that. I also thought it interesting that each of
domUs are running on vcpu0. I figured they would automatically
distribute to a free vcpu.
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