Evaluating the Auto Scaling Performance of Flexiscale and Amazon EC2 Clouds

Nowadays cloud computing is becoming one of the most used technological solution to achieve scalability and reduce costs. Scalability is a key point for the success of any business involving the Web and providing services to end-user requests that may vary drastically from one time to another. Sizing a system to provide performance guarantees under peak traffic can be cost prohibitive; the main advantage of cloud computing lays in the opportunity to allocate resources on-demand on a pay per use basis. In this paper we extend Flexiscale public cloud with auto scaling mechanisms and compare these mechanisms with those offered by Amazon. The analysis aims at identifying useful patterns for the execution of Web applications in the cloud and at underlining the critical factors that affect the performance of the two providers. We performed a large set of experiments that demonstrated the importance of tuning correctly the auto scaling parameters.