Abstract: With the developing of the architecture of IP-networked storage, the iSCSI and the NFS protocols have been more and more widely used in LAN environments. The iSCSI and the NFS performance are experimentally compared, and the read/write process’s system overheads of the iSCSI initiator and the NFS server in specified hardware circumstances are analyzed. The data forwarding procession of the standard iSCSI based NFS server is tested based on an overall considering of the impact of various factors including the workloads, the asynchronous operations and the network latency. The results show that, with different request sizes and different ratios of read/write requests, the system overhead rate of both protocols changes. Consequently, the iSCSI based NFS server should properly adjust the allocation of system resources according to the factors mentioned above to get the best storage system performance.

Key words: Network File System（NFS）, Internet Small Computer System Interface（iSCSI）, protocol overhead, clock cycle, pass-through server, data forwarding

摘要： 随着IP网络存储体系的发展，iSCSI和NFS协议在局域网环境中的应用越来越广泛。实验性地比较iSCSI和NFS的性能，在具体硬件环境中分析了iSCSI initiator和NFS server读写进程的系统开销。对依附iSCSI存储的NFS服务器中的数据转发过程进行测试，综合考虑网络传输、异步读写以及工作流等因素产生的影响。实验结果显示，根据不同的请求数据大小以及读写比例，两者的系统开销比率也随之变化。因此，依附iSCSI存储的NFS服务器应该根据以上因素合理调整资源分配，从而获得良好的存储系统性能。

关键词: 网络文件系统（NFS）, Internet小型计算机系统接口（iSCSI）, 协议开销, 时钟周期, 数据传递服务器, 数据转发