METHOD AND APPARATUS FOR BUILDING AND MANAGING MULTI-CLUSTERED COMPUTER SYSTEMS

One application of clustered computer systems is to support failover of applications and shared resources. Another is to support scalable or fault-tolerant distributed applications. The present invention utilizes a higher-level clustering mechanism (a multi-cluster) overlayed on top of multiple underlying clusters (subclusters) to extend their capabilities. In the described embodiment, subclusters supporting application and shared resource failover across a smaller number of nodes is overlayed with a multi-cluster supporting a larger number of nodes. The multi-cluster manages cluster-level communication among nodes, and the subclusters directly manage only the shared device and application resources which they are permitted to control. It is possible to move resources between nodes which reside in different subclusters. The multi-cluster layer also externalizes interfaces similar to those of the subclusters, providing application compatibility.