7.0_STABLE NetBSD 7.0_STABLE (XEN3_DOM0) #10 and xenkernel45-4.5.5nb1 breaks LVM-backed DomUs

[Kevin.Buckley%ecs.vuw.ac.nz@localhost]

We had an x86_64 Dom0 machine running

 7.0_STABLE NetBSD 7.0_STABLE (XEN3_DOM0) #6  and   xenkernel45-4.5.3

that was happily hosting LVM-backed VBDs for DomUs/.


The machine was recently updated, without changes to the DomU cfg, to

 7.0_STABLE NetBSD 7.0_STABLE (XEN3_DOM0) #10 and xenkernel45-4.5.5nb1


Attemptinhg to "xl create" the DomU worked before results in

libxl: error: libxl_create.c:1155:domcreate_launch_dm: unable to add disk
devices
libxl: error: libxl_device.c:851:libxl__initiate_device_remove: unable to
get my domid
libxl: error: libxl.c:1671:devices_destroy_cb: libxl__devices_destroy
failed for 1
libxl: info: libxl.c:1717:devices_destroy_cb: forked pid 97 for destroy of
domain 1

The disk line in the DomU cfg is

 disk = [ 'phy:/dev/mapper/vg_xen_vbds-ln_name,xvda,w' ]


Not clear to us if this is an issue with what the new Kernel+LVM
is presenting to Xen, or an issue with the new Xen handling what
is being presented to it, or both.

The bloke who did the update doesn't have any other machines hosting
LVM-backed VBDs and I'm not aware of any other Dom0s, that would only
be hosting file-backed VBDs, having been updated here as yet, so we
can't narrow anything down to the LVM-backed nature of this particular
Dom0.

Any clues or things to look for

--

Kevin M. Buckley

eScience Consultant
School of Engineering and Computer Science
Victoria University of Wellington
New Zealand