Modeling User - Perceived Reliability Based on User Behavior Graphs

Service Reliability is an important consideration for new service deployment. Traditional system-oriented measures are no longer adequate to describe the reliability perceived by the user. In this paper we propose a general service reliability analysis approach based on user behavior, and derive formulas to compute service reliability from the user model and service models. The derived user-perceived service reliability incorporates the user task reliabilities, the dependencies of different user tasks, and various types of user behavior besides failure and recovery of system hardware and software components. This approach is applied to the service reliability computation for an example fault tolerant cluster hosing two services. Factors from both the system side and the user side are analyzed for the user-perceived service reliability of the cluster, and the results are compared with the system availability and service reliability lower bound.