Integrated QOS management for disk I/O

We address the problem of providing different 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 different levels of performance guarantees in a single system. The proposed method uses admission control and bandwidth allocation to isolate the different categories 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, provides significantly better performance than SCAN