[Fedora-xen] Backing Up a Xen Guest ..

[Graham Jenkins]

Here's the problem. We perform full tar backups of our CentOS 4
machines in real-time at regular intervals. And when a disaster happens,
we are able to restore those backups onto virgin filesystems, make
the /dev/null, /dev/zero and /dev/console devices .. and boot the
machine.

This has worked well on standalone systems, and also on Xen 3.0.3 guests
on CentOS 4.4 machines, where each guest filesystem resides on regular
(Xen-host) real filesystem.

But there's no way we've been able to make it work for FC6 
guests on FC6 Xen hosts, where each guest disk resides in a
file.

The strategy goes something like:

      * losetup -o 32256 /dev/loop0 /XenGuests/Guest1
      * mkfs -t ext3 /dev/loop0
      * mount -t ext3 /dev/loop0 /mnt
      * cd /mnt && tar xjpf /tmp/Guest1.tbz
      * for i in console null zero; do /sbin/MAKEDEV -d /mnt -x $i; done
      * cd /tmp; umount /srv/vm1; losetup -d /dev/loop0
      * xm create -c Guest1

And it always gets most of the way through .. then the guest dies. I'm
guessing it's got something to do with getting the guest grub to write
boot blocks.

Ideas anyone .. please?

-- 
 Graham Jenkins +61 3 9925 4909 
 Victorian Partnership for Advanced Computing http://www.vpac.org/
 PO Box 201, Carlton South, Vic. 3053, Australia