Distributed token management in calypso file system

Abstract

This paper presents the design and implementation of a distributed token manager for a cluster-optimized, distributed Unix file system. In this file system, tokens provide cache consistency and support for single-system Unix semantics. The paper describes the token types used, token arbitration protocol, deadlock-free implementation, fault-tolerance, and recovery. The key contributions of the work reported here are: (1) An efficient protocol for token arbitration, which minimizes bottlenecks and hence enhances scalability; (2) A practical approach to handling deadlocks, race conditions, and recovery issues, which complicate token manager design and implementation.