[virt-tools-list] Live migration of iscsi based targets

[Gildas Bayard]

Hello,

I'm using libvirt and KVM for a dozen of virtual servers. Each virtual 
server's disk is an iscsi LUN that is mounted by the physical host blade 
which runs KVM.
Every thing works fine at that stage for about a year. Both the servers 
and the blade are running ubuntu server 10.04 LTS.
I've been trying live migration for a while but it was not working, at 
least with my setup, on previous versions of ubuntu (actually 
virt-manager was showing the VM on the target host but the machine 
became unreachable by the network).

Anyway for some reasons it's working now. But there's a big pb: let say 
I use 2 blades (A and B) to host my VMs. If I start a VM on blade A and 
live migrate it to blade B everything is fine. But if I migrate it back 
to blade A awful things happen: at first it's ok but sooner or later the 
VM will complain about disk corruption and destroy itself more and more 
as time goes by. Oops!

My understanding is that blade A got it's iscsi disk cache up and 
running and that when the VM comes back, blade A has no way to know that 
the VM got its disk altered by its stay on blade B for a while. Hence 
the corruption.

Am I getting this correct? Should I switch to NFS "disk in a file" 
instead of using iscsi?

Sincerely,
Gildas