A distributed storage system allowing application users to reserve I/O performance in advance for achieving SLA

Performance assurance has become an important aspect in grid and cloud computing which provide services over the Internet, and Service Level Agreements (SLA) are frequently contracted between users and the service providers. However, the I/O performance of the storage or data access service is still provided on a best effort basis. Some distributed storage systems implement performance reservation, but the reservation is implemented inside of the storage and works in an adaptive manner. In order to promise performance guarantees to users, we propose a distributed storage system allowing application users to explicitly make an advanced and time-based reservation for I/O access and storage space. Thus the requested performance is guaranteed during the reserved time. This paper describes our proposed concept and the design architecture of the storage system, including the reservation interface, resource management and I/O control frameworks. Then it explains our prototype which implements a simple resource allocation strategy and I/O control of the storage network along the design. The experiment results using the prototype are also shown. They indicate that the reservation cost entailed only a low performance impact on users, and that the requested performance was achieved by the reservation feature.