Page 16 of 18 Fibre Channel: Why another interface? March 2001 The following table compares the major characteristics of SCSI bus, Ethernet, and Fibre Channel technologies. The data storage challenge Many companies meet their initial storage needs by using a SCSI bus to connect a tape drive or a library to each server. As the amount of data and number of servers increases, this simple one-to-one approach becomes unmanageable. Often, the next step is to attach the tape drives or library to a dedicated backup server. Unfortunately, moving the large volumes of data over the network to the backup server seriously degrades both backup and overall system performance. In today’s demanding environment, companies cannot afford the reduced network performance or schedule sufficient network down time to allow for adequate data protection. One of the most promising solutions to this data storage dilemma is the Storage Area Network (SAN), a separate network dedicated to data-storage traffic. This dedicated network can move huge amounts of data quickly to and from storage without interrupting data availability or network performance. Fibre Channel’s numerous advantages over traditional bus or network connections make it ideally suited for use in SANs. Because it was specifically designed for high-speed data transfer, Fibre Channel is the interface technology of choice for providing flexible, reliable, high-performance sharing of data storage and backup resources among multiple servers. SCSI Ethernet Fibre Channel Topology Daisy chain Point-to-point, switched fabric Point-to-point, arbitrated loop, switched fabric Current maximum data transfer rate 20 MB/sec (SCSI-2) 160 MB/sec (SCSI-3) 1.25 to 12.5 MB/sec (10/100 BaseT Ethernet) 125 MB/sec (Gigabit Ethernet)^{a a}Gigabit Ethernet is a new 1000 BaseT Ethernet implementation intended to provide high-speed data transfer capability for local area and wide area networks. 200 MB/sec Maximum distance between devices 6 meters, single-ended, 25 meters, differential 30 meters (copper) 10 to 30 kilometers (fiber optic) 30 meters (copper) 10 to 30 kilometers (fiber optic) Supported protocols SCSI SCSI, IP, HIPPI, many others SCSI, IP, HIPPI, many others Maximum number of attached devices 8 (SCSI-1) 16 (SCSI-2, SCSI-3) unlimited 127 (single arbitrated loop) 16 million (switched fabric) Comparison of SCSI, Ethernet, and Fibre Channel Companies today face the challenge of meeting 24/7/365 data availability requirements while at the same time protecting their valuable data with regularly scheduled backups. p1   p2   p3   p4   p5   p6   p7   p8   p9   p10   p11   p12   p13   p14   p15   p16   p17   p18