High availability has become increasingly important to businesses with the advent of the Web and various associated e-commerce services. This paper describes the key attributes of the very highest availability systems. Such systems and their associated support environments are qualitatively different than other systems, even other high availability systems; for the purposes of this paper these systems at the current limit of possible availability are termed extreme availability systems.
Coleman, David W. and Mummert, Todd W., "Extreme Availability: Determining the Limits of Availability in Commercial Systems" (2004). ICEB 2004 Proceedings (Beijing, China). 38.