[DRBD-user] Problems using image files with drbd, maybe unsupported?

[Bart Coninckx]

On Wednesday 06 October 2010 10:51:54 Martin Fandel wrote:
> Hi,
> 
> hearbeat does the same as I do in the following steps:
> 
> drbd disconnect all
> drbd primary all
> mount /dev/drbd0 /var/lib/xen/images
> 
> However, in a heartbeat environment, the xen images are also damaged. If
> the primary node fails, all xen images located in /var/lib/xen/images are
> inconsistent and not bootable.
> 
> I can avoid this by using fsck on the images. But I don't know how use fsck
> on image files. Does anybody know this?
> 
> Thanks!
> 
> Regards,
> 
> Martin
> 
> -------- Original-Nachricht --------
> 
> > Datum: Tue, 5 Oct 2010 21:59:06 +0200
> > Von: Bart Coninckx <bart.coninckx at telenet.be>
> > An: drbd-user at lists.linbit.com
> > CC: "Martin Fandel" <pingu.freak at gmx.de>
> > Betreff: Re: [DRBD-user] Problems using image files with drbd, maybe
> > unsupported?
> > 
> > On Tuesday 05 October 2010 12:26:08 Martin Fandel wrote:
> > > Hi,
> > > 
> > > I'm not sure if I understand the documentation correct. I've installed
> > > SLES10 with DRBD and Xen. I added an drbd-device /dev/drbd0 for the xen
> > > image files. The drbd device /dev/drbd0 is created with ext3 and is
> > > mounted to /var/lib/xen/images. Under this directory, 10 vms are
> > > installed. If I do an switch to the backup machine, xen can't start the
> > > image files / the guest. The kernel says:
> > > 
> > > [87585.519596] EXT3-fs: INFO: recovery required on readonly filesystem.
> > > [87585.519602] EXT3-fs: write access unavailable, cannot proceed.
> > > 
> > > Is it possible, that image files with drbd are not supported? I've also
> > > found an tutorial on google. In the tutorial is a notice, that the
> > > image files must be dumped to dedicated drbd partitions?
> > > 
> > > Thanks!
> > > 
> > > Regards,
> > > 
> > > Martin
> > 
> > You need to install the heartbeat rpms for SLES10 and configure DRBD
> > resources
> > so the DRBD resource becomes active after failover.
> > 
> > B.

I probably should have mentionned that a resource for a ext3 volume should 
also be made, so that with planned failovers you get a clean result. However, 
this is not the best thing to happen for running Xen guests, because they will 
sense their storage has just been swept from under their feet. So you also 
need to add Xen resources. Personally with SLES 10 I would run guests on iSCSI 
storage hosted by DRBD and Heartbeat.

B.