Management methods in SLA-aware distributed storage systems

Traditional data storage systems provide access to user’s data on the "best effort" basis. While this paradigm is sufficient in many use cases it becomes an obstacle for applications with Quality of Service (QoS) constraints. Service Level Agreement (SLA) is a part of the contract agreed between the service provider and the client and contains a set of well defined QoS requirements regarding the provided service and the penalties applied in case of violations. In the paper we propose a set of SLA parameters and QoS metrics relevant to data storage processes and the management methods necessary for avoiding SLA violations. A key assumption in the proposed approach is that the underlying distributed storage system does not provide functionality for resource or bandwidth reservation for a given client request.