【作者】 汪波；

【导师】 谢长生；

【作者基本信息】 华中科技大学 ， 计算机系统结构， 2004， 硕士

【摘要】 存储区域网(SAN)是存储领域的一项重要技术,由存储服务器,存储设备和网络组成。大多数SAN采用SCSI协议作为不同存储设备的公共协议。运用IP和以太网技术,可以构建可扩展,易管理的IP SAN。iSCSI协议是IP SAN中实现存储设备访问的重要协议标准,它将SCSI协议、TCP/IP协议有效融合在一起,在TCP/IP网络上传输SCSI数据,访问IP网络中的SCSI I/O设备。iSCSI的协议数据单元iSCSI PDU包括头部和数据,被封装在TCP包中。iSCSI协议的层次位于TCP/IP之上。这里所实现的跨平台的iSCSI系统可包括多种操作系统平台的服务器和存储设备,服务器以动态可扩展方式访问异地存储资源。通过对iSCSI协议和iSCSI异构系统结构进行分析,针对Windows2000和Linux操作系统的服务器以及Linux平台下的存储设备,分别用不同的服务例程实现iSCSI启动器功能和iSCSI目标器功能,并通过基于主机的虚拟存储方法——LUN Masking,将用户请求映射到相应的逻辑单元,实现存储单元的动态可扩展。iSCSI的服务器端通过图形界面的Web控制管理台管理存储资源。对不同条件下iSCSI实验测试。配置百兆以太网和千兆以太网的交换机和网卡,从测试结果可以得出结论,网络带宽影响系统的性能。千兆以太网中iSCSI的最高速度可达30MB/s以上。多线程能够有效的利用空余资源,因此多线程的iSCSI可以获得更好的性能。操作系统平台的选择也会影响性能,运行在Linux中的iSCSI与Windows2000相比有更高的数传率。最后尝试通过RAM Cache技术、双Cache缓存等改进技术提高iSCSI的性能。实验数据表明,写操作的时间可以减少30%以上。更多还原

【Abstract】 A Storage-Area Network(SAN) is a important technology in storage field that comprises storage servers(initiators),storage devices(targets) and a network. Most SANs use the SCSI protocol over various storage devices. The IP and Ethernet technologies pushes the IP SAN evolution toward a truly scalable, manageable storage system. The iSCSI protocol is an important protocol to accesss storage device in IP SAN. It uses SCSI protocol and TCP/IP protocol that enable a transport for SCSI over TCP/IP and accessing SCSI I/O devices over an IP network. iSCSI defines its own packets that are referred to as iSCSI Protocol Units(PDUs). iSCSI PDUs consist of a header and possible data. iSCSI PDU is sent as the content of one or more TCP packets because iSCSI runs on the top of TCP/IP.Severs and devices in iSCSI system can be designed to run in different OS platforms. Servers work in a dynamic way to extend storage resource. By the analysing iSCSI protocol and iSCSI system, Different server routines are developed to support iSCSI servers and devices under different OS platforms. The device that user request is translated to logic unit by LUN Masking based on host virtualize technology. By this means,storage devices are dynamically extended.The experiments are based on different conditions. We configured the switch and network cards as 100Mbit network and Gigabit network. According to the result of iSCSI performance test, it is concluded that network bandwidth has a impact on performance data. It is also shown that multi-thread system works better than single thread system because multi-thread can use spare resource. Different OSs make different results. iSCSI run faster under Linux than under Windows2000. At last, we implement RAM Cache、double Cache technology to improve the performance of iSCSI. According to experiments data, write time can be reduced over 30%.更多还原