Patent ID: 8364775

Claim:
A computer-implemented method to manage availability of a plurality of slave components executing in a distributed system by maintaining, for at least a first slave component selected from the plurality of slave components, an availability state indicating a health status of the first slave component, the method comprising: sending a plurality of multicast heartbeat requests to the plurality of slave components executing in the distributed system; for each multicast heartbeat request, monitoring whether a unicast heartbeat acknowledgment is received from the respective slave component, responsive to the respective multicast heartbeat request; upon determining that a count of unicast heartbeat acknowledgments not received from the first slave component exceeds a first predefined threshold, transitioning from a slave live state for the first slave component to a slave suspect state for the first slave component; wherein subsequent to transitioning to the slave suspect state, receipt of a unicast heartbeat acknowledgment from the first slave component causes a transition to the slave live state; and upon determining that the count of unicast heartbeat acknowledgments not received from the first slave component exceeds a second predefined threshold greater than the first predefined threshold, transitioning from the slave suspect state to a slave unknown state for the first slave component and by operation of one or more computer processors; wherein subsequent receipt of a unicast heartbeat acknowledgment from the first slave component does not cause any transition from the slave unknown state to the slave suspect state or to the slave live state; wherein subsequent to transitioning to the slave unknown state, a successful restart of the first slave component causes a transition to one of the slave live state and the slave suspect state.