Re: Recently moved to XS 8.2 on new hardware - seen a couple of FreeBSD DomU lock ups?

On Thu, Oct 13, 2022 at 11:00:17AM +0100, Karl Pielorz wrote:
> 
> Hi all,
> 
> We've been running FreeBSD as a DomU under Xen Server for years now, and
> only really had a few now 'known' issues (e.g. with networking).
> 
> We've recently setup XS 8.2 on some new Dell servers, and whilst everything
> appears fine - twice now in a couple of weeks we've had FreeBSD DomU's just
> "lock up".
> 
> There's no errors logged, no kernel panic, nothing - they just "stop". Xen
> reckons the CPU is pegged at 100% (with brief periods of zero) - the console
> is still 'available' (but locked up) - and the kernel is dead (i.e. you
> cannot ping it).
> 
> Aside from the "Has anyone else seen similar" - with nothing in the logs, no
> panic, nothing - I'm kind of at a loss as to how best to troubleshoot this
> further?
> 
> The VM's are lightly loaded - haven't run out of resources (RAM /CPU etc.) -
> and it's only happened a couple of times now (but in a couple of weeks) -
> whereas our setup before never experienced this in it's lifetime.
> 
> One was a legacy 11.4 system (amd64) - the other was a 12.3 system (amd64).
> 
> A forced reboot brings them back (with some file system damage - as you'd
> expect from a crash).
> 
> Just at a loss as to where to look - given the lack of any panic/errors etc.
> Any suggestions?

Hello,

Sorry, been very busy this week and forgot to reply earlier.

Could you try to setup a watchdog in FreeBSD and see if that
triggers?  So that we can get an idea of where the guest locks up.

Is also the 100% load on all CPUs, or just one?

If the watchdog doesn't work we can try other methods.

Thanks, Roger.