The document presents a stochastic model using Stochastic Reward Nets (SRNs) to analyze the performance and quality of service (QoS) in IaaS cloud computing systems, addressing challenges in evaluating resource management strategies. It highlights the limitations of existing systems such as black box approaches to performance evaluation and proposes a scalable, flexible model capable of representing both physical and virtual resources. Additionally, it details system architecture, modules, and evaluates performance metrics to guide system managers in optimizing resource utilization.