Thanks. But why the confusion about vMotion? I suppose that as long as both ESXi hosts are able to see the same VMFS datastores where the VMs are stored vMotion would work, no?
Currently I'm not backing up the VMDK's per se, there's a Backup Agent installed on each of the servers where data is important. Actually, one of the reasons why I'm asking this is to also understand a little better some good practices for VMDK backups.