[Xen-users] Problem booting a restored PVM

[Terry Phelps <tgphelps50@xxxxxxxxx>]

I am trying to develop a procedure for backup and restore of a Xen
PVM. I am having a problem with booting the restored machine. I'll
tell you the symptom, and then what I'm doing to get to that symptom.

When I boot the VM, it panics with a message that says:

"According to mtab, /dev/xvda2 is already mounted on /sysroot"

I don't understand exactly what this means, so i don't know what to
look at to fix it.

Here is what I'm doing:
First, I'm working with Oracle VM Server 3, which uses Xen 4.1.2. I
know Linux fairly well, but I don't know much about Xen yet.

I understand that the kernel in a VM is booted from outside the VM at
startup time, and that grub in the VM is NOT used, except for
providing the grub.conf file that is used to determine which kernel to
boot. IS THIS TRUE?

Anyhow, I have assumed this true, and am trying to "clone" a PVM in
the following way:
1. Backup all the files on the two partitions of my real VM. These are
'/' and '/boot'.
2. Create a new virtual disk and attach it to a running VM.
3. Partition the disk to match the one I'm cloning.
4. Create the / and /boot filesystems.
5. Run mkswap on the swap partition.
6. Restore the files backed up in step 1 to the new disk.
7. Edit /etc/fstab on the new disk, and put in the new UUIDs.
8. Edit /boot/grub/grub.conf on the new disk, and change the
"root=UUID=..." parameter to point to the root filesystem on the new
disk.
9. Create a new VM, make the new disk the boot disk, and boot it.

Note that did NOT do anything to the MBR, nor did I install grub on
the disk. DO I NEED TO?

In any case, the new VM does boot, and does know what the root
partition should be. But then it panics with the message above, and I
don't know what to do next. I have added the "rdshell" parameter to
the kernel line in grub.conf, and have looked around, but I don't see
anything obviously wrong.

Can some smart Xen Person please assist me?

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