[libvirt] Live migration sanity checks

[Konrad Rzeszutek]

> amount of host 'setup'. If a guest is using iSCSI as its storage, then
> there is a step where the host has to login to the iSCSI target and create
> device nodes for the LUNs before the guest can be run. You don't want 
> every single host to be logged into all your iSCSI targets all the time.

I am interested to know why you think this is a no-no. If you have a
set of hosts and you want to be able to migrate between all of them and your
shared storage is iSCSI why would it make a difference whether you had logged in
or logged in on the migrate on each host? 

What about if the shared storage was Fibre Channel and it was zoned so that
_all_ nodes saw the disk. Should you disconnect the block device when not in
usage?