System resilience modeling and enhancement for the cloud

It has become increasingly evident that large scale systems such as clouds can be brittle and may exhibit unpredictable behavior when faced with unexpected disturbances. Even weak and innocuous disturbances can bring down the system inoperative and may introduce catastrophic disasters to the society. The goal of this research is to explore the fundamental theories that govern cloud system resilience and to provide novel and effective mechanisms to model and enhance the resilience of cloud. A food web like process interaction model is developed and system resilience enhancement mechanisms are proposed based on the control of the strength of interactions. Also, the effectiveness and limitations of modularization on resilience enhancement is illustrated by using a replica consistency control protocol. The research has shown that weakening key process interactions and modularizing complex systems are very effective on resilience enhancement.