Addressing Open Issues on Performances Evaluation in Cloud Computing

The Cloud Computing paradigm has been an incredible success in the last few years. It is based on the idea of delegate to the Cloud provider every kind of resources, and let the users access them in a self-service fashion. The Cloud paradigm has largely been adopted in several different contexts and applied to an incredibly large set of technologies. It is an opportunity for IT users to reduce costs and increase efficiency providing an alternative way of using IT services. It represents both a technology for using computing infrastructures in a more efficient way and a business model for selling computing resources. It gives to small and medium enterprises the possibility of using services and technologies that were prerogative of large ones, by paying only for the resources needed and avoiding upfront investment. The possibility of dynamically acquire and use resources and services on the base of a pay-per-use model, implies incredible flexibility in terms of management, which is otherwise often hard to address. On the other hand, because of this flexibility new problems emerge, which involve the evaluation and monitoring of the quality of the acquired resources and services as well as threats that can compromise performance and availability of services provided to final users. This chapter describes some open challenges to performance evaluation and provisioning in Cloud, and presents a survey on the solutions and technologies proposed by research and open community to face such issues.