QoS Adaptation in Service-Oriented Grids

Some applications utilizing Grid computing infrastructure require the simultaneous allocation of resources, such as compute servers, networks, memory, disk storage and other specialized resources. Collaborative working and visualization is one example of such applications. In this context, Quality of Service (QoS) is related to Grid services, and not just to the network connecting these services. With the emerging interest in service-oriented Grids, resources may be advertised and traded as services based on a Service Level Agreement (SLA). Such a SLA must include both general and technical specifications, including pricing policy and properties of the resources required to execute the service – to ensure QoS requirements are satisfied. A QoS adaptation algorithm is presented to enable the dynamic adjustment of behavior of an application based on changes in the pre-defined SLA. The approach is particularly useful if workload or network traffic changes in unpredictable ways during an active session. The proposed QoS adaptation scheme is used to compensate for QoS degradation and optimize resource utilization, by increasing the number of requests managed over a particular time.