Implementing highly-available WWW servers based on passive object replication

We investigate issues related to building highly available World Wide Web (WWW) servers on workstation clusters. We present a novel architecture that includes a dynamic Domain Name System (DNS) and a WWW server based on passive object replication. This architecture allows us to reduce the service down-time of a WWW server without impacting on the Hyper Text Transfer Protocol (HTTP) protocol (and thus on the WWW client software). We implement this architecture in our department and we show some experimental results that analyze, given a batch of HTTP requests, the average response time to a request and the average time of WWW service unavailability due to object crashes.