Towards Building A Conflict-free Mobile Distributed File System

摘要

The rising demand for mobile computing has created a need for an improved file system that supports mobile clients. Current file systems with support for mobility provide availability through file replicas that are cached at the client side. However, mobile clients may experience different obstacles with regards to the local cache, such as the limited network bandwidth, the intermittent connection, and serious conflicts when synchronizing back to the server. In this paper, we propose a novel mobile distributed file system design, which provides high availability and reliable storage for files and guarantees that file operations are executed regardless of concurrency and failure issues. The design is intended to fit mobile clients (e.g. PDAs and cell phones) that have limited storage space and cannot store all of the data they need, and yet require access to these data at all times. We adopt a server-side caching in order to guarantee sufficient caching space to all mobile clients, and to ensure the availability of files in the case of clients' failures. We present our algorithm, describe its implementation, simulate its high availability functions, and report on its performance evaluation using a cluster of workstations. Our simulation results indicate clearly that our algorithm exhibits a significant degree of automation and conflict-free mobile file system.