Re: XEN 3 DomU loses network and dies

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Jan 23, 2008 at 08:39:11AM +0100, Damian Lubosch wrote:
> Manuel Bouyer schrieb:
> >
> >
> > There's no balloon driver at all in NetBSD. All memory allocations to
> > domains are static.
> > But, the hypervisor is then unable to reclaim memory if it evers gets low.
> > How much free memory does xm info (or xm top) reports, and how many
> > virtual disk and network interfaces to you have in dom0 ?
> >
> >   
> Hi Manuel!
> 
> Because of the balloon driver I wondered because the amount of used
> memory (in xm top) varies a little bit around the maximum.

That's expected, it's the pages that are transfered between domains for I/O.
It shouldn't change much.

> When I set up the system  (dom0 + 5 domUs) xm info / top reported about
> 50 MB free RAM for the hypervisor, and after the problems began I
> switched off one domU to get about 108 MB of free RAM but the problems
> still persists.

50MB may be a bit short, especially if you have lots of domUs. I would
expect 100MB to be enough, but I've always had more than 200MB free on my
Xen servers.

> 
> I recompiled the dom0 kernel to having 64 vnd devices and the default of
> xbd devices. In my /dev I generated 16 of both.
> 
> The problem still occured yesterday. But most of the times I was able to
> login via the console over the dom0 to the problem making domU, then I
> had to "shutdown -r now" and on the next boot it stopped after telling
> (I think it was) "unknown type console at xenbus0 id 0 not configured"
> (I'll post the error message when it happens again). I had to go then to
> the dom0 xm shutdown the domU and to recreate it again.

Next time could you look at the output of ifconfig, for the interfaces
in the domU, and the corresponding xvif interfaces in the dom0 ?

-- 
Manuel Bouyer, LIP6, Universite Paris VI.           
Manuel.Bouyer%lip6.fr@localhost
     NetBSD: 26 ans d'experience feront toujours la difference
--