NinjaMail: the design of a high-performance clustered, distributed e-mail system

In today's Internet era, electronic mail is replacing telephony and postal mail as the primary means of communication for hundreds of millions of individuals. Free e-mail services, such as Microsoft's Hotmail and Yahoo's Yahoo Mail, each have tens of millions of subscribers. However, these and other current e-mail systems unfortunately are nor capable of handling the scale of Internet e-mail use, while still providing reliable, high performance and feature-rich services to users. This limitation is the result both of suboptimal use of cluster computing resources, and of highly variable performance of wide-area connections over the Internet. This paper presents NinjaMail, a novel geographically distributed, cluster-based e-mail system built on top of UC Berkeley's Ninja cluster architecture and OceanStore wide-area data storage architecture. NinjaMail is unique in that it uses a collection of clusters distributed through the wide-area to provide users with highly available, scalable and feature-rich services via a wide variety of access methods.