Consistency and locking for distributing updates to web servers using a file system

Abstract

Distributed file systems are often used to replicate a Web site's content among its many servers. However, for content that needs to be dynamically updated and distributed to many servers, file system locking protocols exhibit high latency and heavy network usage. Poor performance arises because the Web-serving workload differs from the assumed workload. To address the shortcomings of file systems, we introduce the publish consistency model well suited to the Web-serving workload and implement it in the producer-consumer locking protocol. A comparison of this protocol against other file system protocols by simulation shows that producer-consumer locking removes almost all latency due to protocol overhead and significantly reduces network load.