Transparent Information Dissemination

This paper describes Transparent Replication through Invalidation and Prefetching (<I>TRIP</I>), a self tuning data replication middleware system that enables transparent replication of large-scale information dissemination services. The TRIP middleware is a key building block for constructing <I>information dissemination</I> services, a class of services where updates occur at an origin server and reads occur at a number of replicas; examples information dissemination services include content distribution networks such as Akamai [1] and IBM's Sport and Event replication system [2]. Furthermore, the TRIP middleware can be used to build key parts of general applications that distribute content such as file systems, distributed databases, and publish-subscribe systems.Our data replication middleware supports <I>transparent</I> replication by providing two crucial properties: (1) sequential consistency to avoid introducing anomalous behavior to increasingly complex services and (2) self-tuning transmission of updates to maximize performance and availability given available system resources. Our analysis of simulations and our evaluation of a prototype support the hypothesis that it is feasible to provide transparent replication for dissemination services. For example, in simulations, our system's performance is a factor of three to four faster than a demand-based middleware system for a wide range of configurations.