Integrated QOS management for disk I/O

In this paper, we address the problem of providing dierent levels of performance guarantees or quality-of-service (QOS) for disk I/O. We classify disk requests into three categories based on the provided level of service. We propose an integrated scheme that provides dierent levels of performance guarantees in a single system. The proposed method uses admission control and bandwidth allocation to isolate the dierent cate-gories of requests and appropriate disk scheduling to achieve the desired performance goals. It is shown that the proposed method achieves the performance goals of individual requests while allowing seek optimizations at the disk. In particular, it is shown that the proposed scheme for integrated QOS management at disk pro-vides signicantly better performance than SCAN.