Architectural design for resilience

Resilience has become a new nonfunctional requirement for information systems. Many design decisions have to be made at the architectural level in order to deliver an information system with the resilience property. This paper discusses the relationships between resilience and other architectural properties such as scalability, reliability, and consistency. A corollary is derived from the CAP theorem, and states that it is impossible for a system to have all three properties of consistency, resilience and partition-tolerance. We present seven architectural constraints for resilience. The constraints are elicited from good architectural practices for developing reliable and fault-tolerant systems and the state-of-the-art technologies in distributed computing. These constraints provide a comprehensive reference for architectural design towards resilience.