It’s important to note that Live Migration (and Vmotion) are used for planned downtime. If your cluster node goes down, you can’t migrate off it (that’s what failover is for). When Live Migrating, the limitation is that only 1 Migration can occur per node. If you have a 12 node cluster, you could have up to 6 simultaneous Live Migrations occurring. This is more than VMware (which restricts you to two simultaneous Vmotions per cluster, regardless of the number of nodes).