Real-time disk scheduling algorithm allowing concurrent I/O requests

Staelin, Carl ; Amir, Gidi ; Ben-Ovadia, David ; Dagan, Ram ; Melamed, Michael ; Staas, Dave

HP Development Company

关键词: real-time disk scheduling;    storage systems;    operating systems;    RAID;   

RP-ID  :  HPL-2009-344

学科分类：计算机科学（综合）

美国|英语

来源: HP Labs

【 摘 要 】

We present a real-time disk scheduling algorithm, Concurrent DS-SCAN (CDS-SCAN), which maximizes throughput for modern storage devices by allowing concurrent I/O requests at the device whenever possible. Past real-time disk scheduling algorithms allowed a single request at a time to go to the storage device, which dramatically reduces the utilization and throughput for modern storage devices, such as RAID arrays and disks with efficient positional-aware scheduling algorithms. We extended the DS-SCAN algorithm so that it can properly account for multiple outstanding I/O requests and guarantee real-time constraints for both outstanding and pending real-time requests. We demonstrate CDS-SCAN's performance on a storage array.