Performance indicator evaluation for a cloud computing system from QoS viewpoint

With the development of information technology, the cloud computing system (CCS) has become a new paradigm for the business and clients. The system supervisor has to guarantee the CCS keeps a good quality of service (QoS) to satisfy the clients' requirements. The maintenance action is thus necessary when the CCS falls to a specific state such that it cannot afford enough capacity to meet demand d. In order to measure the service level of a CCS, this paper constructs a network model and proposes a key performance indicator (KPI), where the KPI is utilized to evaluate the probability that the demand can be satisfied under both transmission time and maintenance budget constraints. A method to derive the interval estimation for the KPI is developed. The system supervisor can conduct the sensitive analysis to improve/investigate the most important part in a large CCS afterwards.