A SCSI target emulator is used in a storage area network （SAN） environment to simulate the behavior of a SCSI target for processing and responding to I/O requests issued by initiators. The SCSI target emulator works...A SCSI target emulator is used in a storage area network （SAN） environment to simulate the behavior of a SCSI target for processing and responding to I/O requests issued by initiators. The SCSI target emulator works with general storage devices with multiple transport protocols. The target emulator utilizes a protocol conversion module that translates the SCSI protocols to a variety of storage devices and implements the multi-RAID-level configuration and storage visualization functions. Moreover, the target emulator implements RAM caching, multi-queuing, and request merging to effectively improve the I/O response speed of the general storage devices. The throughput and average response times of the target emulator for block sizes of 4 KB to 128 KB are 150% faster for reads and 67% faster for writes than the existing emulator. With a block size of 16 KB, the I/O latency of the target emulator is only about 20% that of the existing emulator.展开更多
Storage area networks （SAN） generally use fiber channel （FC） disks, but they are expensive, hard to scale, and incompatible with previous storage arrays. This paper describes an SCSI interface disk array, which is...Storage area networks （SAN） generally use fiber channel （FC） disks, but they are expensive, hard to scale, and incompatible with previous storage arrays. This paper describes an SCSI interface disk array, which is controlled by a simulated target controller, as the target device of an SAN system. A detailed target- mode SCSI middle level design and implementation is described with interfaces to efficiently supervise the entire target simulator. The target simulator has control flexibility, wide applicability, reduced SAN system cost, and compatibility with current SAN systems. The present mass data storage system uses a 2-Gb/s fiber network. Performance and compatibility tests demonstrate the efficiency of the target simulator design.展开更多
Fibre channel storage area networks (FC-SAN) are effective solutions to address storage man- agement problems caused by very large volumes of data. But the expense of fibre channel devices limits FC-SAN applications...Fibre channel storage area networks (FC-SAN) are effective solutions to address storage man- agement problems caused by very large volumes of data. But the expense of fibre channel devices limits FC-SAN applications. The use of IP networks instead of fibre channel networks will reduce SAN cost, but will also reduce the performance. Therefore, small computer system interface (SCSI) devices were consid- ered to replace FC disks to reduce the SAN cost. A driver for the FC network adapter and the FC target, de- signed and implemented to support this structure, obeys the SCSI protocol and works in target mode with 200 MB/s bandwidth. The FC target architecture and implementation were compared with the FC initiator. The SCSI command transfer process in the FC layer was described. The performance test results show that the maximum I/O throughput reachs 167 MB/s for read requests and 196 MB/s for write requests (FC band- width is 200 MB/s), verifying that the FC target is very efficient. The modularization, efficiency, and low cost of the FC target will enable SAN and fibre channel to be more widely used in applications.展开更多
基金Supported by the National High-Tech Research and Development (863) Program of China (No. 2001AA111110)
文摘A SCSI target emulator is used in a storage area network （SAN） environment to simulate the behavior of a SCSI target for processing and responding to I/O requests issued by initiators. The SCSI target emulator works with general storage devices with multiple transport protocols. The target emulator utilizes a protocol conversion module that translates the SCSI protocols to a variety of storage devices and implements the multi-RAID-level configuration and storage visualization functions. Moreover, the target emulator implements RAM caching, multi-queuing, and request merging to effectively improve the I/O response speed of the general storage devices. The throughput and average response times of the target emulator for block sizes of 4 KB to 128 KB are 150% faster for reads and 67% faster for writes than the existing emulator. With a block size of 16 KB, the I/O latency of the target emulator is only about 20% that of the existing emulator.
基金Supported by the National Key Basic Research (973) Program of China(No. 2004CB318205) and the National High-Tech Research and De-velopment (863) Program of China (No. 2004AA111120)
文摘Storage area networks （SAN） generally use fiber channel （FC） disks, but they are expensive, hard to scale, and incompatible with previous storage arrays. This paper describes an SCSI interface disk array, which is controlled by a simulated target controller, as the target device of an SAN system. A detailed target- mode SCSI middle level design and implementation is described with interfaces to efficiently supervise the entire target simulator. The target simulator has control flexibility, wide applicability, reduced SAN system cost, and compatibility with current SAN systems. The present mass data storage system uses a 2-Gb/s fiber network. Performance and compatibility tests demonstrate the efficiency of the target simulator design.
基金Supported by the National High-Tech Research and Development Program (863) of China (No.2001AA111110)
文摘Fibre channel storage area networks (FC-SAN) are effective solutions to address storage man- agement problems caused by very large volumes of data. But the expense of fibre channel devices limits FC-SAN applications. The use of IP networks instead of fibre channel networks will reduce SAN cost, but will also reduce the performance. Therefore, small computer system interface (SCSI) devices were consid- ered to replace FC disks to reduce the SAN cost. A driver for the FC network adapter and the FC target, de- signed and implemented to support this structure, obeys the SCSI protocol and works in target mode with 200 MB/s bandwidth. The FC target architecture and implementation were compared with the FC initiator. The SCSI command transfer process in the FC layer was described. The performance test results show that the maximum I/O throughput reachs 167 MB/s for read requests and 196 MB/s for write requests (FC band- width is 200 MB/s), verifying that the FC target is very efficient. The modularization, efficiency, and low cost of the FC target will enable SAN and fibre channel to be more widely used in applications.
