Modeling user perceived unavailability due to long response times

In this paper, we introduce a simple analytical modeling approach for computing service unavailability due to long response time, for infinite and finite single-server systems as well as for multi-server systems. Closed-form equations of system unavailability based on the conditional response time distributions are derived and sensitivity analyses are carried out to analyze the impact of long response time on service unavailability. The evaluation provides practical quantitative results that can help distributed system developers in design decisions