SCSI子系统中间层多启动互连多路径I/O的存储方式的研究  

Research of the Storage Mode of SCSI Subsystem Mid-Level Multi-Initiated Interconnect Multi-Path I/O

作　　者：蔡斌[1] 谢长生[1] 任劲[1] 

机构地区：[1]华中科技大学计算机学院外存储系统国家重点实验室,湖北武汉430074

出　　处：《小型微型计算机系统》2005年第8期1420-1426,共7页Journal of Chinese Computer Systems

基　　金：国家自然科学基金项目(60173043)资助;国家"八六三"项目(2001AH111011)资助

摘　　要：面对当前应用对现代存储的高性能以及可用性、可靠性的新的要求,在Multi-Initiator-Uni-Port的基础之上提出了SCSI中间层多启动互连多路径I/O的存储方式.它能够在Multi-Initiator—Uni-Port的连接中对同一个Target端口采用不同的I/O路径进行存储,减少了由于单路径I/O传输错误导致系统单点失效的可能性,增强了存储系统的可用性和可靠性;同时,这种存储方式还能够很好地平衡系统的I/O负载,提高系统的吞吐率,提供比传统单路径更好的传输性能.在Linux2.4内核中的SCSI子系统的基础之上实现了这种存储方式,向系统屏蔽了SCSI子系统中的设备具体细节,并且不依赖于SCSI上层的实现,减少了对系统内核的资源占有率,提高了SCSI底层的执行效率.分析了SCSI中间层多启动互连多路径I/O的存储方式的原理,并且将iSCSI的体系结构应用到它的模拟测试中,得到了R-R路径选择分配策略的性能临界点。In the face of the current application＇s new requirement to the availability and reliability of modern storage, this paper puts forward a new storage mode named the SCSI Mid-level Multi-Initiated Interconnect Multi-Path I/O mode, which can carry out I/O to the same Target Port among multi-Initiator-Uni-Port connection, This storage mode reduces the possibility of system＇s single-point invalidation, and improves the system＇s availability and reliability as well; and at the same time, this storage mode can balance the system＇s workload, improve the system＇s throughput, and provide better transmission performance than conventional single I/O path. This paper implements this storage mode in the SCSI subsystem under Linux 2. 4 kernel. It hides the device＇s details of the SCSI subsystem, meanwhile, the implementation does not depend on the implementation of SCSI Upper-level, reduces the usage of the kernel resource and improves the efficiency of the SCSI Low-level as well.This paper analyzes the principle of the SCSI Mid-level Multi-Initiated Interconnect Multi-Path I/O mode, and utilizes the iSCSI architecture into the simulation test, meanwhile, this paper acquires the critical point of the R-R path selection-assignment strategy. The result is satisfactory.

关 键 词：SCSI中间层 Multi—Initiator-Uni—Port Initiator—Target ISCSI 多启动互连 多路径I/O Linux LLDD PROC文件系统 SMPfs文件系统 

分 类 号：TP333[自动化与计算机技术—计算机系统结构]