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Re: Xen support on Squeeze

On Thu, Apr 01, 2010 at 03:40:40PM -0400, Micah Anderson wrote:
> "Nikita V. Youshchenko" <yoush@debian.org> writes:
> >> We have had to carry that patch without any upstream support (or sharing
> >> with Novell, which eventually released SLES 11 with 2.6.27).  As a
> >> result, the xen-flavour kernels for lenny are very buggy, particularly
> >> for domains with multiple vCPUs (though that *may* be fixed now).
> >
> > Unfortunately it is not fixed.
> >
> > We here once migrated to xen and now rely on it, and that gives lots of 
> > frustration. For any loaded domain we still have to run etch kernel, 
> > because lenny kernel constantly crashes after several days of heavy load. 
> > Dom0's run lenny kernel - and with a fix for #542250 they don't crash, but 
> > those are almost unloaded.
> I was having problems with multiple vCPUs also, under moderate load I
> would regularly get crashes. I reported my findings in #504805. I
> swapped out machines, didn't work. When the fix for the xen_spin_wait()
> came out, I eagerly switched to that, but it didn't fix my problem. I
> even tried my hardest to switch to the latest upstream Xen kernel to see
> if that would fix things, but it was way too unstable and I couldn't get
> it to work at all.

What do you exactly mean with the 'upstream Xen kernel' ?

> Eventually I stumbled on a way to keep my machines from restarting, its
> not a great solution, but it stops me from having to deal with the
> failure on a daily basis. I think that anyone else who is having this
> problem can do this and it will work. Obviously this is not the right
> solution, but it works until we can get a fix.
> First I made sure this was set:
> /etc/xen/xend-config.sxp: (dom0-cpus 0)
> Then I pinned individual physical CPUs to specific domU's, once pinned,
> the problem stops.

vcpu pinning is not required for a properly working kernel..

Although good to hear there's a workaround.

-- Pasi

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