[PVE-User] CPU soft lookup

Mykel at mWare.ca Mykel at mWare.ca
Sat Feb 26 16:14:55 CET 2011

On 11-02-26 08:30, Lars Wilke wrote:
> I am experiencing reproducible KVM VM crashes/hangs and once a lost network config, when doing backups
> via vzdump on the Hypervisor. Most of the time the VM just got stuck and i have to shut it down via
> qm stop. Note the problem only occurs with the VM which i am backing up and sometimes with this vm when
> copying large files on the HV node.

What CPU are you using? I've recently discovered that the 2000-series 
Opterons can be very unreliable under high IO loads with KVM. I upgraded 
my KVM hosts to Xeons and the problem went away instantly.

Subsequently, I had a kernel guy (bcrl) spend some time trying to fix 
it, but the crashes were never consistent. In fact, almost never the 
same twice. After a month, we gave up and will use the hardware for 
other purposes. (They're great for OpenVZ VMs.)
A great way to reproduce the crash would be to run a virus scan inside a 
Windows XP KVM. FreeBSD VMs would also go down frequently. Linux VMs 
were a lot more reliable, but would die occasionally too.


PS: I never really got much reaction from this list to my woes, so 
either y'all think I'm half-cocked crazy, or it's just not interesting 
to anyone else ;)

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