Research And Design Of The I/O Schedule Module For RAID System

Emerging video surveillance, large-scale sensor networks, and storage-bound Web applications require large, high-performance, and reliable storage systems with high data-throughput as well as short response times for interactive requests. This is the background enlarging the boosting market of RAID (Redundant Arrays of Inexpensive Disks), which is a best solution for modern storage demands.With an embedded processor, the RAID controller can off-load the major I/O processing workload from the CPU, and at the same time, increase the I/O performance. This paper addresses the essential issue in the design of disks scheduling for RAID devices. According to the characters of the RAID system, we proposed the I/O gathering method. To improve the intelligence of the I/O gathering, we combined it with two indications: tasks’weighted-miss-ratio and fuzzy task satisfaction index. These two indications evaluate the scheduling result of the waiting queue, and also act as the feedback of the status of the RAID disks. We also designed a new parallel scheduling module using this new method for RAID 0, RAID 10, and RAID 5.We also simulated the scheduling module and demonstrated the advantage of the new schedule method.