Where are they located? We have two data centers in Santa Clara County [Calif.], one data center in Sacramento [Calif.] and one in Denver. When you address eBay or make a request of eBay, you have an equal chance of hitting any of those four.So you have, say, 50 database servers per site?Approximately. And it takes about 50 or so to run the site. Not including search systems. Do Denver and Santa Clara mirror Sacramento, for example? No. Weve taken a unique approach with respect to our infrastructure. In a typical disaster recovery scenario, you have to have 200 percent of your capacity100 percent in one location, 100 percent in another locationwhich is cost-ineffective. We have three centers, each with 50 percent of the traffic, actually 55 percent, adding in some bursts. What hardware platform are you on now? We use Sun [Microsystems Inc.] systems, as we did before. We use Hitachi Data Systems [Corp.] storage on Brocade [Communications Systems Inc.] SANs [storage area networks] running Oracle [Corp.] databases and partner with Microsoft for the [Web server] operating system. IBM provides front and middle tiers, and we use WebSphere as the application server running our J2EE codethe stuff that is eBay. The code is also migrated from C++ to Java, for the most part. Eighty percent of the site runs with Java within WebSphere. Did you look at Microsoft .Net? We did, and we thought that using a J2EE-compliant system gave us a lot more flexibility with respect to the other components in our architecture. .Net was definitely a viable solution, and Microsofts a wonderful partner. But we wanted the extra flexibility of being able to port to other application servers and other underlying infrastructures. How long will this architecture last? We believe the infrastructure we have today will allow us to scale nearly indefinitely. There are always little growth bumps, new things that we experience, and not a whole lot of folks from whom we can learn. But using the principles of scaling out, rather than scaling up; disaggregating wherever possible; attempting to avoid state, because state is very costly and increases your failure rate; partnering with folks like Microsoft and IBM, Sun, Hitachi Data Systems, where they feel they have skin in the game and are actually helping us to build something; and then investing in our people, along with commodity hardware and softwareapplying those principles, we think we can go indefinitely. Would it make more sense to go with a commodity Intel [Corp.]-architecture back end? Were in a continuous state of re-evaluation, and were not afraid to swap out where necessary. With the help of Sun people, weve tuned the applications to take advantage of the benefits of their systems. There would be a bit of work to change, but should the time come where we believe theres a significant benefit, we would probably make that move. Suns recent strategy, with their alliance with AMD [Advanced Micro Devices Inc.], shows that they are willing to move toward the commodity space. Were actually running a pilot of that architecture, AMD-based Sun servers with a Linux variant. Next Page: eBay open all night.