The Andrew File System is a location-transparent distributed tile system that will eventually span more than 5000 workstations at Carnegie Mellon University. Large scale affects performance and complicates system operation. In this paper we present observations of a prototype implementation, motivate changes in the areas of cache validation, server process structure, name translation, and low-level storage representation, and quantitatively demonstrate Andrews ability to scale gracefully. We establish the importance of whole-file transfer and caching in Andrew by comparing its performance with that of Sun Microsystems NFS tile system. We also show how the aggregation of files into volumes improves the operability of the system.

Andrew is a distributed computing environment being developed in a joint project by Carnegie Mellon University and IBM. One of the major components of Andrew is a distributed file system which constitutes underlying mechanism for sharing information. The goals of the Andrew file system are to support growth up to at least 7000 workstations (one for each student, faculty member, and staff at Carnegie Mellon) while providing users, application programs, and system administrators with the amenities of a shared file system.