Coordinated Checkpoint versus Message Log for Fault Tolerant MPI

MPI is one of the most adopted programming models for Large Clusters and Grid deployments. However, these systems often suffer from network or node failures. This raises the issue of selecting a fault tolerance approach for MPI. Automatic and transparent ones are based on either coordinated checkpointing or message logging associated with uncoordinated checkpoint. They are many protocols, implementations and optimizations for these approaches but few results about their comparison. Coordinated checkpoint has the advantage of a very low overhead on fault free executions. In contrary a message logging protocol systematically adds a significant message transfer penalty. The drawbacks of coordinated checkpoint come from its synchronization cost at checkpoint and restart times. In this paper we implement, evaluate and compare the two kinds of protocols with a special emphasis on their respective performance according to fault frequency. The main conclusion (under our experimental conditions) is that message logging becomes relevant for a large scale cluster from one fault every hour for applications with large dataset.