Design and Optimization of an iSCSI System

摘要

Data storage plays a critical role in today's fast-growing data-intensive network services. iSCSI is a new standard that allows SCSI protocols to be carried out over IP networks. This paper introduces a software iSCSI implementation and proposes two mechanisms to improve the performance of the IP SAN. One is the appropriate algorithm to manage commands on the SCSI command queue, such as an elevator algorithm to prioritize commands, and algorithms to eliminate or concatenate SCSI commands. The other mechanism is the use of a cache algorithm on the iSCSI target server. We have implemented these optimized algorithms and tested the performance of the IP SAN. The results show that the optimized system's throughput reaches 85MB/S, which consumes 90% of the total IP network bandwidth and greatly reduces the average response time. Our IP storage system shows improved performance compared with the current iSCSI implementation.