Para aquellos que se atrevan con el inglés, aquí tienen un video sobre el cluster de máquinas que soportan toda la carga de trabajo de Google. El video es del 2002 pero sigue siendo muy interesante:

Google’s Linux cluster currently processes over 150 million queries a day, searching a multi-terabyte web index for every query with an average response time of less than a quarter of a second, with near-100% uptime. In this discussion, Google Fellow Urs Hölzle will describe the software and hardware infrastructure that makes this performance possible, as well as provide an overview of the main problems facing a web search, software architecture, servers and compact rack hardware designs.

http://www.researchchannel.org/prog/displayevent.asp?rid=1680

Fuente: SIG-IR Resources (Videos IR Talks)