Infrastructure Software

I have a virtual disk that refuses to attach. It is xvdq in the vm.cfg below. I have tried a reboot of the guest VM but that does not help.
I searched for any mention of xvdq in /var/log/messages or dmesg and found nothing. I think there must be a problem in Dom-0. The xm block-list command lists some very different information for one of the devices which is prbably the one that won't mount, but I'm really not knowledgable enough yet to know how to interpret it.

Any suggestions or places to look for more insight into what's wrong?

[root@bznorvm03 150_bznvordbd03p]# cat vm.cfg
bootloader = '/usr/bin/pygrub'
disk = ['file:/var/ovs/mount/0ECDB3010FF94D7B9FA0620F7CD43825/running_pool/150_bznvordbd03p/System.img,xvda,w',
'phy:/dev/mpath/LUN310,xvdb,w!',
'phy:/dev/mpath/LUN404,xvdc,w!',
'phy:/dev/mpath/LUN503,xvdd,w!',
'phy:/dev/mpath/LUN403,xvde,w!',
'phy:/dev/mpath/LUN001,xvdf,w!',
'phy:/dev/mpath/LUN305,xvdg,w!',
'phy:/dev/mpath/LUN306,xvdh,w!',
'phy:/dev/mpath/LUN307,xvdi,w!',
'phy:/dev/mpath/LUN308,xvdj,w!',
'phy:/dev/mpath/LUN309,xvdk,w!',
'phy:/dev/mpath/LUN311,xvdl,w!',
'phy:/dev/mpath/LUN402,xvdm,w!',
'phy:/dev/mpath/LUN501,xvdn,w!',
'phy:/dev/mpath/LUN502,xvdo,w!',
'file:/var/ovs/mount/0ECDB3010FF94D7B9FA0620F7CD43825/running_pool/150_bznvordbd03p/vd01.img,xvdp,w',
'file:/var/ovs/mount/0ECDB3010FF94D7B9FA0620F7CD43825/running_pool/150_bznvordbd03p/vd02.img,xvdq,w',
]

[root@bznorvm03 150_bznvordbd03p]# xm block-list 10
Vdev BE handle state evt-ch ring-ref BE-path
51712 0 0 4 11 8 /local/domain/0/backend/vbd/10/51712
51728 0 0 4 12 9 /local/domain/0/backend/vbd/10/51728
51744 0 0 4 13 10 /local/domain/0/backend/vbd/10/51744
51760 0 0 4 14 11 /local/domain/0/backend/vbd/10/51760
51776 0 0 4 15 12 /local/domain/0/backend/vbd/10/51776
51792 0 0 4 16 13 /local/domain/0/backend/vbd/10/51792
51808 0 0 4 17 14 /local/domain/0/backend/vbd/10/51808
51824 0 0 4 18 15 /local/domain/0/backend/vbd/10/51824
51840 0 0 4 19 16 /local/domain/0/backend/vbd/10/51840
51856 0 0 4 20 17 /local/domain/0/backend/vbd/10/51856
51872 0 0 4 21 18 /local/domain/0/backend/vbd/10/51872
51888 0 0 4 22 19 /local/domain/0/backend/vbd/10/51888
51904 0 0 4 23 20 /local/domain/0/backend/vbd/10/51904
51920 0 0 4 24 21 /local/domain/0/backend/vbd/10/51920
51936 0 0 4 25 22 /local/domain/0/backend/vbd/10/51936
51952 0 0 4 26 23 /local/domain/0/backend/vbd/10/51952
268439552 0 0 6 -1 -1 /local/domain/0/backend/vbd/10/268439552