Modeling Correlated Failures in Survivable Storage Systems

The design of survivable storage systems involves inherent trade-offs among properties such as performance, security, and availability. A toolbox of simple and accurate models of these properties allows a designer to make informed decisions. This paper focuses on availability modeling. We describe two ways of extending the classic model with a single “correlation parameter” to accommodate correlated failures. We evaluate the efficacy of the models by comparing their results with real measurements.