Implementing and Evaluating Automatic Checkpointing

As the size and popularity of computer clusters go on growing, fault tolerance is becoming a crucial factor to ensure high performance and reliability for applications. To provide this facility, a checkpoint mechanism is used to recover a failed parallel application rolling it back to an execution moment prior to occurrence of the failure. In this work we present a mechanism for managing checkpoint operations during the failures automatically. This mechanism records periodically the application´s context, identifies failed nodes and restarts MPI processes on the remaining nodes, allowing the continuity of the application and taking advantage of the computing accomplished previously. We describe a lot of changes inside source of the LAM/MPI. Experiments with an application for recognizing DNA similarity showed that despite the overhead caused by periodic checkpoints, the benefits can reach about 50% on a small cluster.