Re: [Xen-users] powerdown problem on XEN

[Atom2 <ariel.atom2@xxxxxxxxxx>]

Hi Ian,
many thanks for your suggestions and for helping out in trying to get to 
the roots of this issue. Sorry for my delay in responding - setting up a 
serial console took a bit of time, but please see my inline comments below.
Thanks.

Am 07.08.13 10:39, schrieb Ian Campbell:
> On Mon, 2013-07-29 at 00:03 +0200, Atom2 wrote:
> > Hi guys,
> > I have a problem with powering down my system under the XEN hypervisor.
> > System details are as follows:
> >
> > gentoo linux, X86_64
> > XEN version 4.2.2
> > linux hardened kernel 3.9.5 as dom0
> > Xeon E3 1260L processor (vt-d capable)
> > 32GB ECC RAM which has been thoroughly tested - so should be o.k.
> >
> > when I issue "shutdown -h now" from dom0 the system usually reboots
> > instead of turning off power to the machine. There's the odd occassion
> > (probably 1 in every 10 to 20 shutdown attempts) when the system power
> > is actually turned off. There seems to be no rule to follow when this
> > happens.
> >
> > If I use the exact same kernel and start w/o the XEN hypervisor
> > powerdown *always* works as expected when I use "shutdown -h now". So on
> > the face of it, this seems to point to the XEN hypervisor as the culprit.
> >
> > Any idea/help on how to track down and solve the issue would be very
> > much appreciated. If you require any more information / log data, I'm
> > more than happy to provide that.
> You could try the Xen reboot= option, which controls which hardware
> mechanism tries to use to reboot. See
> http://xenbits.xen.org/docs/unstable/misc/xen-command-line.html for
> details.
None of the options listed in your link (reboot=b|t|k|n|w|c) managed to 
turn off power to the system. All but reboot=n (and also noreboot=true) 
did a reboot after requesting a powerdown with shutdown -h now.
reboot=n or noreboot=true just left the machine's power on with the last 
message on the console (from the gentoo dom0 shutdown) reading
[ <no secs since start> ] Power Down.

> > Unfortuantely however, there seems to be no log / dmesg data available
> > during shutdown as syslog-ng is stopped. The only thing I can confirm
> > that there's no strange output on the console during either bootup or
> > shutdown: All services / daemons start up o.k. and also during shutdown
> > all services seem to come to a proper halt. The root filesystem is
> > re-mounted r/o and the last message reads "Power down" - only to then
> > reboot the system by going through a BIOS power-on sequence.
> I would expect you to see a message to the affect "dom0 has shutdown,
> rebooting" from the hypervisor at the very end. You may need a serial
> console to see this though I suppose.
> http://wiki.xen.org/wiki/Xen_Serial_Console
I have set up a serial console and the output is attached to this mail. 
It did however not contain the message you expected, but that might be 
due to the fact that I did not request a reboot but rather a powerdown. 
At least that's my guess.
> In fact if the reboot= options don't help then setting up a serial
> console to get at Xen's logs during reboot is probably the next step.
>
> Alternatively I think "console=vga vga=current,keep" will keep the VGA
> for Xen so you can see what is happening, but at the expense of no VGA
> for dom0 (I've never actually tried this myself, but I think it should
> work). This might be OK if you can use ssh to initiate the reboot and
> then taker a photo of the resulting Xen logs.
This was my initial try, but I did not manage to get that working. I 
guess, now having the serial console log available, might render this 
useless anyways for my case ...
I hope the attached file helps in narrowing the powerdown problem down. 
If you require any more informatio, I'd be more than happy to provide that.
Many thanks again ...

> Ian.

Attachment: XEN console
Description: Text document

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