Building a multisite Web architecture

Any large organizations that first came online in the late 1990s are now facing the decision whether to upgrade their Web systems or to start anew. Given the speed with which new technologies are introduced in the Web environment, system deployment life cycles have shrunk significantly-but so have system life spans. After only a few years, an organization's Internet infrastructure is likely to need a major overhaul. In late 2001, the systems architecture team to which I belong took on these issues for an organization that wanted to rebuild its Web infrastructure. The existing infrastructure contained multiple single points of failure, could not scale to expected usage patterns, was built on proprietary systems, and had a high management overhead. The legacy infrastructure had grown organically over the previous five years as administrators added unplanned features and functionality, and usage had grown 100-fold since the specifications were initially developed. Because of the age and condition of the legacy systems, we decided to redesign the solution from scratch to overcome the inherent limitations. This case study describes the process our systems architecture team followed for designing and deploying the new architecture. I detail the component selection rationale, with implementation details where allowed. Ours is just one successful approach to deploying a. multisite, fully redundant Web-based system for a large organization; other reasonable and viable ways to build such a system also exist.