xFS: a wide area mass storage file system

The current generation of file systems are inadequate in facing the new technological challenges of wide area networks and massive storage. xFS is a prototype file system we are developing to explore the issues brought about by these technological advances. xFS adapts many of the techniques used in the field of high performance multiprocessor design. It organizes hosts into a hierarchical structure so locality within clusters of workstations can be better exploited. By using an invalidation-based write back cache coherence protocol, xFS minimizes network usage. It exploits the file system naming structure to reduce cache coherence state. xFS also integrates different storage technologies in a uniform manner. Due to its intelligent use of local hosts and local storage, we expect xFS to achieve better performance and availability than current generation network file systems run in the wide area