1. A method for providing a massively parallel processing (MPP) cluster of processing nodes, the method comprising: dividing the MPP cluster into a plurality of sub-clusters of processing nodes; arranging the sub-clusters of processing nodes into a fan-out tree hierarchy; exchanging heart-beat messages between processing nodes in same sub-clusters of processing nodes within limit of each of the corresponding sub-clusters of processing nodes to maintain cluster membership integrity of processing nodes in each of the sub-clusters of processing nodes; and actively suppressing inter-sub-cluster heart-beat traffic to prevent heart-beat traffic exchanged between processing nodes in the same sub-cluster of processing nodes from reaching processing nodes in other sub-clusters of processing nodes.