WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

RE: [Xen-devel] Hotplug scripts not working... xen/ia64 domU stopped wor

To: "Ewan Mellor" <ewan@xxxxxxxxxxxxx>
Subject: RE: [Xen-devel] Hotplug scripts not working... xen/ia64 domU stopped working
From: "Magenheimer, Dan (HP Labs Fort Collins)" <dan.magenheimer@xxxxxx>
Date: Fri, 2 Dec 2005 09:41:39 -0800
Cc: Xen Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Fri, 02 Dec 2005 17:41:27 +0000
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcX22owD117ieNy3RRKgd9aD8TliaQAhX+Vg
Thread-topic: [Xen-devel] Hotplug scripts not working... xen/ia64 domU stopped working
Problem identified but it's a weird one!  I turned on logging
in /etc/xen/scripts/block and /etc/hotplug/xen-backend.agent
using Adam's cool trick of redirecting stderr output (exec 2>>file),
and discovered I *was* getting a message that domain0 already
was using the loopback device.

So I again tried turning on w! in /etc/xen/xmdefconfig
and this time it worked!

However, when I turned off logging, the w! no longer makes
the problem go away, and there is a long pause before the
"Error: Device 769... Hotplug scripts not working" message.
(Logging need only be enabled in xen-backend.agent to
make the problem again go away.)

Some weird timing problem?

My /etc/xen/xmdefconfig is very short:
kernel = "/tmp/xenlinux"
memory = 256
nics=0
disk = ['phy:loop0,hda1,w']  # <-change to w!

and after a fresh boot, I am simply doing:

# lomount -t ext2 -diskimage /var/xen/hda /mnt
# xend start
# xm create

I can see how it could be interpreted that loop0 is
being used both by domain0 and the newly created domain,
but isn't this a common use model?

Dan

P.S. When I change my /etc/xen/xmdefconfig to
disk = ['file:/var/xen/hda,hda1,w']
mounting the root disk fails with:
UDF-fs: No VRS found

> -----Original Message-----
> From: Ewan Mellor [mailto:ewan@xxxxxxxxxxxxx] 
> Sent: Thursday, December 01, 2005 5:51 PM
> To: Magenheimer, Dan (HP Labs Fort Collins)
> Cc: Xen Mailing List
> Subject: Re: [Xen-devel] Hotplug scripts not working... 
> xen/ia64 domU stopped working
> 
> On Thu, Dec 01, 2005 at 04:39:03PM -0800, Magenheimer, Dan 
> (HP Labs Fort Collins) wrote:
> 
> > 
> > > > By "put logging into" do you mean adding a '-x' at the end
> > > > of the first (bin/sh) line?  If so, where is the logging going?
> > > > (not to the console nor to /var/log/xend.log...)  Sorry...
> > > > it's been awhile since I've done script debugging and it's
> > > > definitely a lot different than hypervisor debugging :-}
> > > 
> > > Doing that writes to stderr, which unfortunately is going 
> > > straight down
> > > /dev/null, because this is being run by the kernel's hotplug 
> > > infrastruture.
> > > 
> > > You can either use echo "Message" >~/my-log to write to a log 
> > > file of your own,
> > > or log err "Message" to write to syslog (once you have included
> > > xen-hotplug-common.h).
> > 
> > Any suggestions as to where in the file would be illuminating?
> 
> Just keep shuffling them forward until they stop working ;-)  
> I really have no
> idea -- I'd just binary chop until I found out where the problem was. 
> 
> > And where is "syslog"? (not in /var/log... it's a RHEL3 system)
> 
> /var/log/messages is normal for Redhat, I think.  This is 
> usually configurable
> with /etc/syslog.conf or /etc/syslog-ng.conf, but hardly 
> anyone changes from the
> default!
> 
> > I can confirm now that cset 8048 works and 8049 does not.
> > Using 'w!' does not make any difference.  I don't see any
> > changes in the changeset that look particularly interesting
> > from an ia64 perspective.  Do you see anything new that might
> > reach into the hypervisor that didn't before?  Or perhaps
> > something new with evtchn (which has some differences on ia64)?
> 
> Are you using really long file names for these 
> loopback-mounted disks?  Someone
> reported a failure with filenames greater than 64 chars 
> today.  There's
> nothing IA64-specific that I'm aware of.
> 
> Ewan.
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>