The Research Of IP SAN Technology Based On ISCSI Protocol

With the exponential increasing of data in enterprise, the traditional centralizedstorage solution does not satisfy their requirement. Therefor, the Storage AreaNetwork(SAN) has walk up to the stage of history. But traditional SAN has somedisadvantages such as short distance, high-cost and complex design. As a newtechnology of network storage, iSCSI integrates storage I/O with IP network, and hasan excellent advantage incomparably to other protocols. The IP storage techologybased on iSCSI protocol has become hot issue in network storage.This article researches on IP network storage technology based on iSCSIprotocol. Firstly, it researches on the current popular technology of networkstorage. Then it does some research on the key technology of iSCSI. Speciallyanalyses the some facts that affects the efficieny of the iSCSI procotol.Then, for the low efficiency of iSCSI CRC algorithm, we replace the originalserial CRC by parallel CRC algorithm, and according to the characters of iSCSI, weimprove the parallel CRC algorithm. We propose a new buffer strategy to shorten theresponse time. We use avoidance copying technology to reduce redundant data copy inLinux kernel which can advance the storage sysyem's performance.Finally, based on the research of other experts, we design and implement theiSCSI system which runs in Linux's kernel space. By means of hierarchal modulestructure, it assures the least independent of physical devices, and easy to transplantto embedded Platform. At last, we test two performace measures, the utilizing rate ofCPU and the command delay. And the testing results shows our improvementsdecrease the utilizing rate of the CPU and shorten command delay.