Summary & Conclusions -The limited stable storage available in mobile computing environments can make traditional checkpointing and message logging unsuitable. Since storage on a mobile host is not considered stable, most protocols designed for these environments save the checkpoints on base stations. Previous approaches have assumed that the base station always has sufficient disk space for storing checkpoints. If there is not enough storage available, some checkpoints may need to be aborted. This paper describes an adaptive protocol that manages storage for base stations. The protocol integrates leasing storage management with a time-based coordinated checkpointing mechanism. The leasing enables storage managers to effectively control disk space. Leasing prevents hanged processes from indefinitely retaining storage and, in addition, garbage collection is simple. Time-based 1 checkpointing is integrated with leasing to reduce the number of messages for establishing consistent global states. The checkpointing mechanism makes use of a three-level storage hierarchy to improve checkpointing performance. Performance was evaluated by both implementation experiments and simulations. The results show that the adaptive protocol reduced checkpointing overhead and the leasing mechanism maintained the desired storage assignment for base stations. 2
An adaptive protocol integrating leasing mechanism proposed in REF manages storage for base stations.
Adaptive Checkpointing with Storage Management for Mobile Environments
IEEE Transactions on Reliability
Engineering Computer Science