Research And Implementation Of High-performance Iscsi System

With the rapid development of digital information technology, and the explosive increasing of data, it has promoted the Network-Centric Storage Technology to develop rapidly. The study of the Network Storage Technology based on iSCSI protocol, is currently a major trend in storage field. Constructing iSCSI Storage System with iSCSI has been the important solution to network storage.On current iSCSI technology research, they most focus on theoretical research and protocol-level analysis. This dissertation mainly studies the important research areas of the iSCSI technology: improvement of caching mechanism.The main contributions of this article are summarized as follows:(1) Factors related to the performance of iSCSI protocol are tested and analyzed in detail;(2) Designed and implemented a hash table caching mechanism. The mechanism applies many technologies, such as using hash technology to achieve rapid positioning, applying hash table entries stored the front pointer to link a data list, replacing a cache block with the detection of adaptive replacement algorithm, and timely data synchronization. It is mainly used in the iSCSI system it has enormous storage space in the Target server, which deeply accelerates the command response speed;(3) Designed and implemented a mapping table caching mechanism. The mechanism applies many technologies, such as establishing a one to one mapping table about the cache block address and the disk block address, using mapping table technology to reach rapid positioning with the efficiency of O (1) in order to find the corresponding cache block, replacing the cache block with the Least Frequently Used algorithm, and timely data synchronization. It is mainly used in the iSCSI system it has general storage space in the Target server, which greatly reduces the response time of command;(4) Based on the hash table caching mechanism and the mapping table caching mechanism, a new and high-performance system which greatly reduces the times which the Initiator directly accesses to the Target is proposed and implemented. Initiator and Target are hierarchical designed based on the Linux kernel-level structure, and embedded into the Linux kernel. By testing, the results show that the optimized iSCSI system greatly increased IOPs and MBPs of the system, that is, tremendously improved the overall performance of the iSCSI system;(5) An application example about iSCSI system is proposed. In this example, it uses the iSCSI technology and a specific storage solution is provided.