AW: [Xen-users] Reverse migration breaks/freezes VM

Rustedt, Florian
Tue, 10 Mar 2009 14:55:36 -0000

Hello Horacio,

unfortunately, this wasn't the reason in my case.
The Xenstore did delete the uid as wished, i had no left-over-uid in the
"moving-from" domain.

So i keep on beeing stuck to the "how do i get a working kernel"
problem until now, searching for a stable xen-kernel >2.6.21 that is not from
SLES...

Cheers, Florian


________________________________

	Von: horacio ibrahim [mailto:horacioibrahim@gmail.com]
	Gesendet: Freitag, 6. März 2009 12:52
	An: Rustedt, Florian
	Betreff: Re: [Xen-users] Reverse migration breaks/freezes VM


	Florian,
	when you make migration the entries in xenstore are not clean.

	After migrate: VM1/XEN0 for XEN1 the /vm/UUID of VM1 remains in Xen0.

	(Steps)
	1 - XEN0 - UUID(VM1) = qwert1234 (for to see xenstore-list /vm)

	After migrate
	2- XEN1 - UUID(VM1 - identical as of UUID VM1 XEN0) = qwert1234
	"when move it back again"
	3 - Yet exists UUID in xen0

	Then remove the UUID with # xenstore-rm /vm/$VMUUID.

	More details....

	Before migrate
	[root@xen0 bin]# xenstore-list /vm
	00000000-0000-0000-0000-000000000000
	4aa111c0-003a-625c-0b0d-02a42bd83b43

	Before migrate
	[root@xen1 bin]# xenstore-list /vm
	00000000-0000-0000-0000-000000000000

	After migrate
	[root@xen1 bin]# xenstore-list /vm
	00000000-0000-0000-0000-000000000000
	4aa111c0-003a-625c-0b0d-02a42bd83b43

	"when move it back again"
	[root@xen0 bin]# xenstore-list /vm
	00000000-0000-0000-0000-000000000000
	4aa111c0-003a-625c-0b0d-02a42bd83b43 <---- yet exists



	Here worked.

	Regards,
	Horacio Ibrahim.



	On Fri, Mar 6, 2009 at 7:56 AM, Rustedt, Florian
<Florian.Rustedt@smartnet.de> wrote:


		Hi Thomas,

		can you give me a hint, how i can get a complete xen-patched source-tree for
2.6.28(.xx)?
		Or a xen patch-set for vanilla-sources?
		Or even better, is there perhaps a way for you to give me your kernel-source
tree as download? Then i've got exactly the same version and can be sure to
exclude this topic as failure source..?
		I could provide a ftp-upload location for that, if that helps?

		Of course i read this: http://wiki.xensource.com/xenwiki/XenParavirtOps

		But then i would have a 2.6.29 kernel and for now it would be better, if i get
exact your version that is known to work...?

		Cheers, Florian


		> -----Ursprüngliche Nachricht-----
		> Von: xen-users-bounces@lists.xensource.com
		> [mailto:xen-users-bounces@lists.xensource.com] Im Auftrag von
		> Thomas Halinka
		> Gesendet: Freitag, 6. März 2009 09:35
		> An: Brad Plant
		> Cc: xen-users@lists.xensource.com
		> Betreff: Re: [Xen-users] Reverse migration breaks/freezes VM

		>
		> Hi Florian,
		>
		> Full ACK to Brad,
		>
		> kick the 2.6.27-Kernel. We have some kernel-gurus in here and
		> they will tell you the same. Try 2.6.26 or 2.6.28 and it
		> should work....
		>
		> Best regards,
		>
		> Thomas
		>
		>
		> Am Freitag, den 06.03.2009, 11:09 +1100 schrieb Brad Plant:
		> > Hi Florian,
		> >
		> > I was unable to successfully migrate VMs running a 2.6.27
		> kernel. I found that the network would stop working on the
		> first migration and then the disk IO would stop when
		> migrating the machine back again (which made processes block
		> waiting for disk IO and therefore the machine appear to hang).
		> >
		> > Try a 2.6.28 kernel. It seems to have sorted out my issues.
		> >
		> > Cheers,
		> >
		> > Brad
		> >
		> >
		> > On Thu, 5 Mar 2009 14:12:56 +0100
		> > "Rustedt, Florian" <Florian.Rustedt@smartnet.de>
wrote:
		> >
		> > > Hello list,
		> > >
		> > > I've got strange phenomenons with migrations. I think
it's a bug,
		> > > but am not sure, so i am asking for your help to find this ou,
		> > > please ;)
		> > >
		> > > First the construct:
		> > > Two HP DL180G5(xen0,xen1) with dual-quadcore each, 8G RAM.
		> > >
		> > > On each a dom0 with selfcompiled(because of network
		> drivers) gentoo-sources-xen-2.6.27_amd64 and Xen 3.3.0. The
		> installation is completely the same (rsynct), only different
		> in ip and hostname.
		> > >
		> > > Both share a drbd0(v8.3.0) device. On it an lvm with one
		> lv per vm.
		> > >
		> > > Now what's the problem:
		> > >
		> > > If i migrate a running vm(mx1-smartnet-de) from xen0 to
		> xen1, it seems to work.
		> > > I could do a "xm migrate mx1-smartnet-de xen1"
without
		> any interuption while having a ssh-connection to the vm and
		> downloading a kernel-source in it.
		> > >
		> > > Then i did a "xm migrate mx1-smartnet-de xen0" on
xen1 to
		> move it back again. After that, the vm freezes at 100%CPU and
		> that's it! Can't connect to it any more, whether via ssh nor
		> via vnc/fb or console. Only "xm destroy" could help, "xm
		> shutdown" has no impact.
		> > >
		> > > For debugging, i added the concerning parts of the
		> xend.log from each and the kernel-configs, so that you could
		> try to help me find the prob perhaps in the logs?
		> > >
		> > > Just after having started the vm:
		> > > xen0_after_start_of_vm.log
		> > >
		> > > Then after the first migration:
		> > > xen0_after_migrate_to_xen1_of_vm.log
		> > > xen1_after_migrate_to_xen1_of_vm.log
		> > >
		> > > And last, after the reverse:
		> > > xen0_after_migrate_back_from_xen1_of_vm.log
		> > > xen1_after_migrate_back_from_xen1_of_vm.log
		> > >
		> > > I don't believe it is a drbd/lvm problem, because drbd
		> keeps in "0: cs:Connected ro:Primary/Primary
		> ds:UpToDate/UpToDate C r---" and there are no lv-concerning
		> log-entries in syslog.
		> > >
		> > > There are of course errors concerning "retry suspend
		> domain failed", but there's no hint, WHY this has got failed?
		> > >
		> > > Kind regards, Florian
		> > >
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