Application specific data replication for edge services

Abstract

The emerging edge services architecture promises to improve the availability and performance of web services by replicating servers at geographically distributed sites. A key challenge in such systems is data replication and consistency so that edge server code can manipulate shared data without incurring the availability and performance penalties that would be incurred by accessing a traditional centralized database. This paper explores using a distributed object architecture to build an edge service system for an e-commerce application, an online bookstore represented by the TPC-W benchmark. We take advantage of application specific semantics to design distributed objects to manage a specific subset of shared information using simple and effective consistency models. Our experimental results show that by slightly relaxing consistency within individual distributed objects, we can build an edge service system that is highly available and efficient. For example, in one experiment we find that our object-based edge server system provides a factor of five improvement in response time over a traditional centralized cluster architecture and a factor of nine improvement over an edge service system that distributes code but retains a centralized database.