Cache Coherency in Distriuted File System

Abstract

Principle of locality states that most memory references are made to a small number of memory locations. Not only that, memory locations near most recently referenced locations are more likely to be referenced than one further away. To take advantage of this, cache memory is inserted between memory and CPU [1]. Better utilization of cache is crucial for good performance of distributed file system; even in case of remote file accesses. Not caching a file during writes prolongs the session, thereby increasing write-sharing time, leading to slow performance especially on WANs. This paper introduces a technique to reduce miss penalty during remote file writes and allows write sharing in LAN. It uses the principle of divide-and-rule and arranges the system into hierarchical domains and then gives ownerships to the writers.