[Fedora-xen] Running mixed FC5/FC6 domains

[Andy Burns]

Now that FC6T1 is upon us, I'm wondering if it is supported to run an 
FC6Tx domU as a guest of an FC5 dom0 host? Or an FC5 domU as a guest of 
an FC6 dom0 host? If possible would this require synchronised xen 
versions for guest and host domains?

I see using xen as a good way to make upgrades less painful by live 
migration of guests between hosts while the hosts are upgraded, and by 
splitting functions of a server into multiple guests which can be 
tested/upgraded individually.

Allowing mixed domains could ease the "upgrade treadmill" of Fedora, and 
reduce the possibility of breaking everything at once during upgrades.

Presumably RHEL5 customers will eventually ask the same questions about 
supporting mixed RHEL6 upgrades with xen? Getting this right would give 
xen/linux the "no downtime" functionality I recall from performing 
rolling upgrades across nodes in VMS clusters years ago.

Thoughts?