Hi,
We have a dozen of dom0, running about 50 domUs. All domUs have disks on
LVM, disks are located on a SAN, so it is very easy to live migrate simply
by attaching a domU disk on two dom0s.
All dom0s run CentOS50 with Xen 3.0.3.
We tried many time to migrate in vitro some little domUs and it worked
perfectly.
Now we really need to migrate a big domU (big by its RAM: 3.6 GB) and we
have the following error (log on the from dom0):
[2008-01-10 10:38:08 xend 30141] DEBUG (balloon:127) Balloon: 18520 KiB
free; need 17408; done.
[2008-01-10 10:38:09 xend 30141] DEBUG (XendCheckpoint:83) [xc_save]:
/usr/lib/xen/bin/xc_save 23 1 0 0 1
[2008-01-10 10:38:09 xend 30141] INFO (XendCheckpoint:239) Couldn''t
enable
shadow mode: 12
[2008-01-10 10:38:09 xend 30141] INFO (XendCheckpoint:239) Save exit rc=1
[2008-01-10 10:38:09 xend 30141] ERROR (XendCheckpoint:106) Save failed on
domain ctc31pinl (1).
Traceback (most recent call last):
File "/usr/lib/python2.4/site-packages/xen/xend/XendCheckpoint.py",
line
100, in save
forkHelper(cmd, fd, saveInputHandler, False)
File "/usr/lib/python2.4/site-packages/xen/xend/XendCheckpoint.py",
line
227, in forkHelper
raise XendError("%s failed" % string.join(cmd))
XendError: /usr/lib/xen/bin/xc_save 23 1 0 0 1 failed
Google said that this error may occur when the 2 dom0s have different
CPUs. It was the case at our first trial, we took another dom0 with a
rigourously identical hardware and the error remains the same.
We checked that the target dom0 has enough RAM, and that /var partition is
big enough on both dom0s.
Thanks for help.
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Maximilian Wilhelm
2008-Jan-10 14:54 UTC
Multiple Dom0s sharing a SAN with LVM (was: Re: [Xen-users] Live migration problem)
Am Thursday, den 10 January hub Alain BARTHE folgendes in die Tasten: Hi!> We have a dozen of dom0, running about 50 domUs. All domUs have disks on > LVM, disks are located on a SAN, so it is very easy to live migrate simply > by attaching a domU disk on two dom0s.[...] I''m sorry, I have no answer to your problem, but I would like to ask how exactly you setup your environment. Did you follow any howto on this? I want to setup exactly the same at work, so any tip or usefull link would be appreciated. Thanks a lot! Ciao Max -- Follow the white penguin. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Jan 10, 2008, at 10:53 , Alain BARTHE wrote:> > Hi, > > We have a dozen of dom0, running about 50 domUs. All domUs have > disks on LVM, disks are located on a SAN, so it is very easy to live > migrate simply by attaching a domU disk on two dom0s. > > All dom0s run CentOS50 with Xen 3.0.3. > > We tried many time to migrate in vitro some little domUs and it > worked perfectly. > > Now we really need to migrate a big domU (big by its RAM: 3.6 GB) > and we have the following error (log on the from dom0):Your problem is probably that live migration requires Xen to create a shadow copy of the active RAM of your DomU, so you effectively need to have RAM(DomU) free on the source and 2*RAM(DomU) on the target Dom0. Cheers, Pi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Alain BARTHE
2008-Jan-10 16:45 UTC
RE Multiple Dom0s sharing a SAN with LVM (was: Re: [Xen-users] Livemigration problem)
We don''t follow any how-to for that, but things are quiet simple. We decided that a VG is dedicated for each domU, and one LV on this VG for each disk of the domU (generally only one). We use naming rules to avoid to get lost with this big amount of LVs. When you want to migrate a domU, you must attach the SAN disk on which resides the domU''s VG to the target dom0, and you must activate its LVs. The "xm migrate -l" may be runned, generally it succeeds... except in some cases like the one I reported here. Don''t hesitate to ask me if you have further questions. Auf viedersen. Alain. xen-users-bounces@lists.xensource.com a écrit sur 10/01/2008 15:54:15 :> Am Thursday, den 10 January hub Alain BARTHE folgendes in die Tasten: > > Hi! > > > We have a dozen of dom0, running about 50 domUs. All domUs have diskson> > LVM, disks are located on a SAN, so it is very easy to live migratesimply> > by attaching a domU disk on two dom0s. > [...] > > I''m sorry, I have no answer to your problem, but I would like to ask > how exactly you setup your environment. > Did you follow any howto on this? > > I want to setup exactly the same at work, so any tip or usefull link > would be appreciated. > > Thanks a lot! > > Ciao > Max > -- > Follow the white penguin. > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Maximilian Wilhelm
2008-Jan-10 18:14 UTC
Re: RE Multiple Dom0s sharing a SAN with LVM (was: Re: [Xen-users] Livemigration problem)
Am Thursday, den 10 January hub Alain BARTHE folgendes in die Tasten:> We don''t follow any how-to for that, but things are quiet simple. > We decided that a VG is dedicated for each domU, and one LV on this VG for > each disk of the domU (generally only one). We use naming rules to avoid > to get lost with this big amount of LVs.I also use an LV for each partition of the DomU so you can access the filesystems easily from the Dom0 in case of error.> When you want to migrate a domU, you must attach the SAN disk on which > resides the domU''s VG to the target dom0, and you must activate its LVs. > The "xm migrate -l" may be runned, generally it succeeds... except in some > cases like the one I reported here.So you have an own PV (as in a piece of the SAN) for each DomU? Or do I miss something?> Don''t hesitate to ask me if you have further questions.Thanks! Ciao Max -- Follow the white penguin. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Alain BARTHE
2008-Jan-11 08:18 UTC
Re: RE Multiple Dom0s sharing a SAN with LVM (was: Re: [Xen-users]Livemigration problem)
xen-users-bounces@lists.xensource.com a écrit sur 10/01/2008 19:14:57 :> Am Thursday, den 10 January hub Alain BARTHE folgendes in die Tasten: > > > We don''t follow any how-to for that, but things are quiet simple. > > We decided that a VG is dedicated for each domU, and one LV on this VGfor> > each disk of the domU (generally only one). We use naming rules toavoid> > to get lost with this big amount of LVs. > > I also use an LV for each partition of the DomU so you can access the > filesystems easily from the Dom0 in case of error.We use an LV for the whole disk of the domU, so that domUs may be installed the standard way from a distrib and a kick-start which does the partition stuff. This way, domU are also more independant from domU, and there is less LVs. To access domU partitions from the dom0, we use "kpartx".> > > When you want to migrate a domU, you must attach the SAN disk on which> > resides the domU''s VG to the target dom0, and you must activate itsLVs.> > The "xm migrate -l" may be runned, generally it succeeds... except insome> > cases like the one I reported here. > > So you have an own PV (as in a piece of the SAN) for each DomU? > Or do I miss something?Yes we have. Yes there is a lot of PV as pieces of SAN. I don''t personaly manage the SAN, but it don''t seems to be a hard stuff.> > > Don''t hesitate to ask me if you have further questions. > > Thanks! > > Ciao > Max > -- > Follow the white penguin. > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Jan 10, 2008 10:33 AM, Pim van Riezen <pi@panelsix.com> wrote:> > On Jan 10, 2008, at 10:53 , Alain BARTHE wrote: > > > > > Hi, > > > > We have a dozen of dom0, running about 50 domUs. All domUs have > > disks on LVM, disks are located on a SAN, so it is very easy to live > > migrate simply by attaching a domU disk on two dom0s. > > > > All dom0s run CentOS50 with Xen 3.0.3. > > > > We tried many time to migrate in vitro some little domUs and it > > worked perfectly. > > > > Now we really need to migrate a big domU (big by its RAM: 3.6 GB) > > and we have the following error (log on the from dom0): > > Your problem is probably that live migration requires Xen to create a > shadow copy of the active RAM of your DomU, so you effectively need to > have RAM(DomU) free on the source and 2*RAM(DomU) on the target Dom0. >It shouldn''t be 2*RAM. From what I have read, the amount of memory needed equals the amount of memory allotted to the guest on the source host plus an additional 8MB of temporary storage . I don''t yet have a guess as to why it is actually failing though.> Cheers, > Pi > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users