A Versatile, Proactive Dependability Approach to Handling Unanticipated Events in Distributed Systems

The MEAD system that we are developing employs a synergistic combination of a reactive and a proactive fault-tolerance approach in order to address unanticipated events and hazards in real-time, fault-tolerant distributed systems. The reactive fault-tolerance approach involves active monitoring of the system to adapt the provided QoS and to allocate resources based on current conditions in the system. The proactive approach involves monitoring both the distributed applications and the network to seek pre-cursors to imminent failures, and then to trigger fault-recovery mechanisms in advance of the occurrence of the failure. The underlying ideas of the MEAD system have demonstrated initial promise through our enhanced capabilities to handle failures and unanticipated events, and to reduce jitter under faulty conditions.