ABSTRACT
This chapter discusses reliability and availability modeling issues related to the system represented by state-space models. It uses stochastic Petri nets to evaluate systems not well represented by combinatorial models due to a complex interaction between components or an active-redundancy mechanism. The chapter presents a set of SPN models for the availability and reliability evaluation of systems. It presents a single-component system whose time to failure and time to repair are not exponentially distributed. The chapter depicts an SPN model for cold-standby redundancy. This SPN comprises six transitions, arcs, transitions' attributes, and the initial marking. In computer systems, preventive maintenance is the task of regularly inspecting the computer hardware and software to help ensure that it continues to function correctly. It presents a stochastic model to evaluate IaaS cloud computing systems deployed into geographically distributed data centers as well as taking into account disaster occurrence.
