Re: [Xen-users] Xen & DRBD

Joris Dobbelsteen
2008-03-17T20:17:47Z

Stuart Poulton wrote:
> Dear All,
>
> I''m using drbd to provide a HA pair of servers to run xen domains
on.
>
> I''ve created a test domain as follows
>
> x-host-2:~ # more /etc/xen/vm/opensuse
> name="opensuse"
> ostype="opensuse"
> uuid="ee62226a-8487-cc02-d89f-dafafd1f35e6"
> memory=1214
> vcpus=2
> on_crash="destroy"
> on_poweroff="destroy"
> on_reboot="restart"
> localtime=0
> builder="linux"
> bootloader="/usr/lib/xen/boot/domUloader.py"
> bootargs="--entry=xvda1:/boot/vmlinuz-xen,/boot/initrd-xen"
> extra=" "
> disk=[ ''phy:/dev/drbd0,xvda,w'',]
> vif=[ ''mac=00:16:3e:29:fb:80'', ]
> vfb=[''type=vnc,vncunused=1'']
>
> This works fine, and start and stop the domain on both of the nodes.
> However if I try to use
>
> disk=[ ''drbd:xendomains,xvda,w'',]
>
> I get the following error....
>
> x-host-2:~ # xm create opensuse
> Using config file "/etc/xen/vm/opensuse".
> Error: Disk isn''t accessible
>
If you are using <= 0.7 you must set the disk to master mode to be able
to write to it. On 0.8 it was possible to simultaneously write to both
the master and slave.
Try looking at <http://www.linux-ha.org/>, which has a lot of
information about the subject.

 From a little test I did long ago, I used heartbeat to manage DRBD,
mount the file system and start the service that needed the disk (it
also did graceful shutdown on failback if desired).

- Joris

Disclaimer: version numbers are from volatile memory and might be
incorrect...
> I''m expecting the block-drbd script to do something here, but from
what
> I can tell it''s not.
>
> I suspect I''ve missed something fundamental. Any pointers please ?
>
> Thanks
>
> Stuart