(Internet Small Computer System Interface) Pronounced "eye-scuzzy," iSCSI is a protocol that enables servers to access remote disks as if they were locally attached. iSCSI "initiator" software in the server converts disk block level reads and writes to SCSI commands that are serialized into IP packets that traverse any local IP network or wide area IP network such as the Internet. At the destination side, the iSCSI packets are decoded by the disk drive array into the appropriate commands for the type of disk drives used (SCSI, Fibre Channel, SAS or SATA). See block level.Network Management Is RequirediSCSI traffic generally runs in a subnetwork or virtual LAN to keep it separated from the rest of the LAN. To increase the transfer rate, network cards and iSCSI disk arrays may support port aggregation. For example, four Gigabit Ethernet ports could function as one 4 Gbps Ethernet channel, providing approximately a 400 Mbytes/sec data transfer rate.In addition, iSCSI network switches may be used that are built to optimize the forwarding of iSCSI packets. See IP storage, SCSI, Fibre Channel, SAS and SATA.
A network protocol specified by the Internet Engineering Task Force (IETF) in RFC 3347 (July 2002) for the use of the Small Computer System Interface (SCSI) protocol over TCP/IP networks.As data exits the computer, headed toward the storage device, a host bus adapter (HBA) converts the data to a SCSI format, enclosed in an Internet Protocol (IP) packet, and transmitted over an Ethernet network.An advantage of iSCSI is that it is transparent, as the server software sees what looks to be a SCSI controller and the network sees only IP traffic.The protocols employed at Layers 2, 3, and 4 are Ethernet, IP, and Transmission Control Protocol (TCP). Further, iSCSI is intended to run at speeds up to 10 Gbps over 10 Gigabit Ethernet (10GigE), over IP wide area networks (WANs), and at lower cost than Fibre Channel. See also 10 Gigabit Ethernet, IETF, IP, OSI Reference Model, protocol, SCSI, TCP, Transport Layer, and WAN.
Also see IP SAN.