SaaS performance and scalability evaluation in clouds

Cloud computing not only changes today´s computing infrastructure, but also alters the way of obtaining computing resources, managing and delivering software and services. Meanwhile, cloud computing brings new issues, challenges, and needs in performance testing, evaluation and scalability measurement due to the special features of cloud computing, such as elasticity and scalability. This paper focuses on performance evaluation and scalability measurement issue for Software as a Service (SaaS) in clouds. It proposes new formal graphic models and metrics to evaluate SaaS performance and analyze system scalability in clouds. In addition, the paper reports an evaluation approach based on Amazon´s EC2 cloud technology and detailed case study results using the proposed models and metrics.