added second virtio-disk: disk order detected wrong

["Stefan G. Weichinger" <lists@xxxxxxxx>]

Greets, I am unsure if it's a linux- or libvirt-issue:

I added a 2nd virtio-disk to a kvm-based VM.

The xml shows a correct "target":


# first disk vda

<disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/mnt/r0/vm1_vda-clone.img'/>
      <target dev='vda' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
function='0x0'/>
    </disk>

# second disk vdb

<disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/mnt/r0/www3_var.img'/>
      <target dev='vdb' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
function='0x0'/>
    </disk>


The VM contains Gentoo Linux, grub comes up fine, but then it flips the
devices:

The unpartitioned new disk is vda, therefore there is no root-fs etc ...

I know my way to fix this via Live-CD or so, but I would really like to
understand what happened! I'd like to keep vda as root etc.

Could someone explain?

libvirt-0.8.6 and qemu-kvm-0.13.0-r2 on a gentoo-host, btw.

Thanks, Stefan