Effectual Minimum Process Global Snapshot Compilation Algorithms For Fault Tolerance In Mobile Distributed Systems

Abstract

Coordinated checkpointing is an effective fault tolerant technique in distributed system as it avoids the domino effect and require minimum storage requirement. Most of the earlier coordinated checkpoint algorithms block their computation during checkpointing and forces minimum-process or non-blocking but forces all nodes to takes checkpoint even though many of them may not be necessary or non-blocking minimum-process but takes useless checkpoints or reduced useless checkpoint but has higher synchronization message overhead or has high checkpoint request propagation time. In coordinated checkpointing, if a single process fails to take its checkpoint; all the checkpointing effort goes waste, because, each process has to abort its tentative checkpoint. In order to take its tentative checkpoint, an MH needs to transfer large checkpoint data to its local MSS over wireless channels. The checkpointing effort may be exceedingly high due to frequent aborts especially in mobile systems. We try to minimize the loss of checkpointing effort when any process fails to take its checkpoint in coordination with others. Hence in mobile distributed systems there is a great need of minimizing the number of communication message and checkpointing overhead as it raise new issues such as mobility, low bandwidth of wireless channels, frequently disconnections, limited battery power and lack of reliable stable storage on mobile nodes. In this thesis, we propose a minimum-process coordinated checkpointing algorithm for mobile distributed system where no useless checkpoints are taken, no blocking of processes takes place and enforces a minimum- number of processes to take checkpoints. Our algorithm imposes low memory and computation overheads on MH s and low communication overheads on wireless channels.