Adding Cloud Performance to Service Level Agreements

To some the next iteration of Grid and utility computing, Clouds offer capabilities for the high-availability of a wide range of systems. But it is argued that such systems will only attain acceptance by a larger audience of commercial end-users if binding Service Level Agreements (SLAs) are provided. In this paper, we discuss how to measure and use quality of service (QoS) information to be able to predict availability, quantify risk, and consider liability in case of failure. We explore a set of benchmarks that offer both an interesting characterisation of resource performance variability, and identify how such information might be used both directly by a user and indirectly via a Cloud Broker in the automatic construction of SLAs.