An Efficient Checkpointing Algorithm for Mobile Distributed Systems

Mobile distributed system is a distributed system with mobile node as well as static node. Due to unique characteristic of mobile nodes likes mobility, limited bandwidth on wireless link, limited battery power backup, limited local storage, frequent disconnection and the handoff, traditional fault tolerance scheme can not be directly applied in mobile distributed systems. Non blocking coordinated checkpointing algorithm which forces minimum number of process to take their checkpoint, are preferred approach for mobile distributed systems. To achieve the goal of non-blocking and minimum- process sometimes, it also requires piggybacking of some extra information onto normal messages or taking some useless checkpoints. As during checkpointing lot of checkpointing information including all variables, the environment, control information register value are transmitted through the wireless links. So these forced/useless checkpoints increase the checkpointing overheads as these are transmitted through the wireless link and require large communication bandwidth and energy. Therefore our efforts are mostly directed towards avoiding the useless checkpoints. In this paper we propose a minimum process non-blocking coordinated checkpointing algorithm which does not take any useless checkpoint and produce consistent global state with minimum number of checkpoints. This approach can significantly save battery energy as well as wireless communication bandwidths.