Research On Cache Replacement And Disk Scheduling Algorithms In Network Storage

With the arrival of information age, the value of the information is also more and more high. At the same time, the development at full speed of Internet makes that the data capacity quickly explosion increased, and this brought great pressure to the data storage. It has set higher requirements than in the past in data access performance, data transmission performance data management capabilities and expanded storage capacity. Therefore user's need is the storage system frame that can satisfy the high-capacity data storage requirement now, and also able to suit capacity extending requirement in the future. With the rapid development of multimedia technology, Large-scale multimedia network storage system has become a hot topic. Large-scale multimedia network storage system requires high storage capacity and high I/O throughput. Now I/O becomes a new bottleneck, Cache technology,data placement scheme is the key point that affects the system performance and the corresponding scheduling policy. It is important and meaningful to study data placement and the scheduling policy for storage system of large-scale multimedia network storage, which is researched in this thesis.(1) This paper has explained and described in details the conceptions, characters and applications of DAS, NAS and SAN, it has also compared NAS with SAN. The key technology of SAN application, such as Fiber Channel, iSCSI, InfiniBand, RAID have also been discussed here.(2) A great deal of reference books are consulted and a lot of researches of this field done by others are summaried to increase I/O performance in storage equipment as well as the entire network storage systems, including cache technologies, disk scheduling, data distribution technologies. Research on the cache replacement algorithm based on the replacement cost, which has been testified by exchanging and adding modules, and adopted a new performance evaluation metrics -- average cost per reference, the result shown that the algorithm had good performance. In addition, real-time disk scheduling algorithm, which satisfies multimedia application is studied in this paper, and give the EDF&SSTF disk-scheduling algorithms which is a composition of Earliest Deadline First and Shortest Seek Time First algorithm.