LOW COST CHECKPOINTING AND FAILURE RECOVERY IN MOBILE COMPUTING SYSTEM

Abstract

Mobile computing system raises many new issues, such as lack of stable storage, available communication bandwidth of wireless channel, and the limited battery life. To minimize the lost computation during recovery from node failures, periodic collection of a consistent snapshot of the system (checkpoint) is required. Locating mobile nodes contributes to the checkpointing and recovery costs. Synchronous snapshot collection algorithms, designed for static networks, either force every node in the system to take a new local snapshot, or block the underlying computation during snapshot collection. Hence, they are not suitable for mobile computing systems. If nodes take their local checkpoints independently in an uncoordinated manner, each node may have to store multiple local checkpoints in stable storage. This is not suitable for mobile nodes as they have small memory. This dissertation work deals with the simulation and evaluation of synchronous snapshot collection algorithm for mobile systems in which if a node initiates snapshot collection, local snapshots of only those nodes that have directly or transitively affected the initiator since their last snapshots need to be taken. The global snapshot collection terminates within a finite time of its invocation and the collected global snapshot is consistent. The simulated nonblocking snapshot algorithm has low communication and storage overheads and meets the low energy consumption and low bandwidth constraints of mobile computing systems.