Static Analysis Meets Distributed Fault-Tolerance: Enabling State-Machine Replication with Nondeterminism

Midas is an inter-disciplinary approach to supporting state-machine replication for nondeterministic distributed applications. The approach exploits compile-time static analysis to identify both first-hand and second-hand sources of nondeterminism. Subsequent runtime compensation occurs through either the transfer of nondeterministic checkpoints or the reexecution of inserted code, and restores consistency among replicas before each new client request. The approach avoids the need for lock-step synchronization and leverages application-level insight to address only the nondeterminism that matters. Our preliminary evaluation demonstrates Midas’ feasibility and current performance overheads.