Re: LVM + Xentools 4.1: can't VOP_OPEN device / unknown device

[Christoph Egger <Christoph_Egger%gmx.de@localhost>]

On 18.04.11 19:35, Hugo Silva wrote:
> Like it used to happen with the xentools33 package(*), HVM won't work
> when backed by lvm storage.
> 
> The logs say:
> xbdback backend/vbd/3/768: can't VOP_OPEN device 0xa903: 16
> (for block devices)
> 
> xbdback backend/vbd/2/768: unknown device 0xc203
> (for raw devices)

With xen 4.1 the block devices are backed by qemu-dm.
The kernel xbdback driver continues to work but conflicts with qemu-dm.

If qemu-dm or xbdback driver is used depends on who wins the race.

If you run a DIAGNOSTIC kernel you will see the kernel panicing in
VOP_CLOSE.

You don't see this problem when you start the HVM guest with xl since
the xbdback driver isn't used at all.

Christoph