Performance of Cloud Computing Centers with Multiple Priority Classes

In this paper we consider the general problem of resource provisioning within cloud computing. We analyze the problem of how to allocate resources to different clients such that the service level agreements (SLAs) for all of these clients are met. A model with multiple service request classes generated by different clients is proposed to evaluate the performance of a cloud computing center when multiple SLAs are negotiated between the service provider and its customers. For each class, the SLA is specified by the request rejection probabilities of the clients in that class. The proposed solution supports cloud service providers in the decision making about 1) defining realistic SLAs, 2) the dimensioning of data centers, 3) whether to accept new clients, and 4) the amount of resources to be reserved for high priority clients. We illustrate the potential of the solution by a number of experiments conducted for a large and therefore realistic number of resources.