Multi-disk scheduling for time-constrained requests in RAID-0 devices
In this paper, we study the scheduling problem of real-time disk requests in multi-disk systems, such as RAID-0. We first propose a multi-disk scheduling algorithm, called Least-Remaining-Request-Size-First (LRSF), to improve soft real-time performance of I/O systems. LRSF may be integrated with different real-time/non-real-time single-disk scheduling algorithms, such as SATF and SSEDV, adopted by the disks in a multi-disk system. We then extend LRSF by considering the serving requests on-the-way (OTW) to the target request to minimize the starvation problem for requests that need to retrieve a large amount of data. The pre-fetching issue in RAID-0 is also studied to further improve the I/O performance. The performance of the proposed algorithm and schemes is investigated and compared with other disk scheduling algorithms through a series of experiments using both randomly generated workload and realistic workload.