Linux – Migrate guest from KVM to VirtualBox

kvm-virtualizationlinuxlvmvirtualbox

I'm migrating some machines from KVM to VirtualBox for a transitional period while we build our new virtualization environment.

The problem now, the disks are located on a LVM partition, and I have to convert them to a format VirtualBox recognizes. I've found a lot of documentation for the transition on the other direction, but not on this one.

qemu-img convert -c /dev/Volume01/Disk -O qcow2 Disk.qcow2

The tool seems to do its job, but the disk won't work. On VirtualBox, I get FATAL: No bootable medium found! System halted.. Are there another options?

Best Answer

dd the volume first:

dd if=/dev/Volume01/Disk of=/tmp/image.raw
qemu-img convert -O vdi /tmp/image.raw test.vdi
rm /tmp/image.raw

Technically you could give that raw file to VirtualBox, but VDI is its native format.

Related Solutions

KVM Virtualization – How to Copy KVM Disk Image to LVM

You may simply have an off-by-one math error:

3146776576 (size, in bytes of your .raw file)  / 1024 (kb) / 1024 (mb) == 3001MB

But you made your LV exactly 3000MB ?

There's nothing wrong with DD'ing one partition onto another. Even though your vmbuilder partition list added up to 3000, your .qcow file is a hard drive image, which includes a partition table + mbr @ the front of the disk.

Linux – mount qcow2 snapshots

You should apply the snapshot and mount the image like always. It's better to create a snapshot right before applying if you want to turn back to the original disk contents before you do these operations. After you apply the snapshot you just mount the image with qemu-nbd as always:

# modprobe nbd max_part=8
$ qemu-img snapshot -c backup image.qcow2
$ qemu-img snapshot -a old_snapshot image.qcow2
$ qemu-nbd --connect=/dev/nbd0 image.qcow2
# mount /dev/nbd0p1 /mnt

You might want to save snapshot separately and mount it as another disk drive. For this you should use convert comand for qemu-img.

$ qemu-img convert -s old_snapshot image.qcow2 old_snapshot.qcow2
$ qemu-nbd --connect=/dev/nbd0 old_snapshot.qcow2
# mount /dev/nbd0p1 /mnt

See man qemu-img(1) and qemu-nbd(1) for more details.

Best Answer

Related Solutions

KVM Virtualization – How to Copy KVM Disk Image to LVM

Linux – mount qcow2 snapshots

Related Topic