I don't now much about udev works. But it starts with the highest partition (sdb7 vg: vgswift lv: lvswift as dm-0) of the second disk which is configured for lvm and takes than the next lower partition (sdb6 vg: nova-volumes lv: nova-disk dm-1) and so on. Ok one reason for the working order could be that the first disk sda is an elder SATA-I ST32500N and the disk sdb is an newer SATA-III WD1003FBYX-0.
The "critical" inner vg/lv was created by the following commands.
I don't now much about udev works. But it starts with the highest partition (sdb7 vg: vgswift lv: lvswift as dm-0) of the second disk which is configured for lvm and takes than the next lower partition (sdb6 vg: nova-volumes lv: nova-disk dm-1) and so on. Ok one reason for the working order could be that the first disk sda is an elder SATA-I ST32500N and the disk sdb is an newer SATA-III WD1003FBYX-0.
The "critical" inner vg/lv was created by the following commands.
lvcreate -L 30G -n nova-disk nova-volumes
SR="$( xe sr-create type=ext device- config: device= /dev/nova- volumes/ nova-disk name-label=ext )"
POOL="$( xe pool-list --minimal )"
xe pool-param-set uuid=${POOL} default-SR=${SR}