Nested QoS: Providing Flexible Performance in Shared IO Environment

The increasing popularity of storage and server consolidation introduces new challenges for resource management. In this paper we propose a Nested QoS service model that offers multiple response time guarantees for a workload based on its burstiness. The client workload is filtered into classes based on the Service Level Objective (SLO) and scheduled to provide requests in each class a stipulated response time guarantee. The Nested QoS model provides an intuitive, enforceable, and verifiable SLO between provider and client. The server capacity in the nested model is reduced significantly over a traditional SLO while the performance is only marginally affected.