Soft-Checkpointing Based Coordinated Checkpointing Protocol for Mobile Distributed Systems

Minimum-process coordinated checkpointing is a suitable approach to introduce fault tolerance in mobile distributed systems transparently. It may require blocking of processes, extra synchronization messages or taking some useless checkpoints. Allprocess checkpointing may lead to exceedingly high checkpointing overhead. To optimize both matrices, the checkpointing overhead and the loss of computation on recovery, we propose a hybrid checkpointing algorithm, wherein an all-process coordinated checkpoint is taken after the execution of minimum-process coordinated checkpointing algorithm for a fixed number of times. In the minimum-process coordinated checkpointing algorithm; an effort has been made to optimize the number of useless checkpoints and blocking of processes using probabilistic approach and by computing an interacting set of processes at beginning. We try to reduce the loss of checkpointing effort when any process fails to take its checkpoint in coordination with others. We reduce the size of checkpoint sequence number piggybacked on each computation message.