KVM and RAID1 over IP

[David Ehle <ehle@xxxxxxxxxxxxxxxxx>]

Does anyone here have any experience with using KVM/libvirt with RAID1 
over IP/DRBD or other HA solution?

I'm trying to figure out the hardware configuration I would need to be 
able to survive a failure or planned shutdown of any one unit in a 
virtualization cluster.

KVM/libvirt makes moving running VM's from one host to another a no 
brainer, but I'm trying to figure out the right way to be able to take 
a the storage backend for maintenance without disrupting the VMs.

Right now I'm thinking something like KVM + libvirt + heartbeat/corosync + 
pacemaker + DBRM  on Ubuntu 10.04 with 3 or 4 nodes - 2 hosts, 2 storage, 
or 1 host, 1 host + storage, 1 storage.

Any thoughts?

Thanks!