iSCSI has been a popular additional feature for many of the recent new product launches from vendors, including Thecus, QNAP and NETGEAR who have also introduced iSCSI based routers and switches.

Leading the pack has been Thecus Technology who in August 2006, first announced support and availability of an iSCSI target in their 5-bay N5200 range of Network Attached Storage units, and have since supported the standard successfully within the SMB market segmentation for all 5-bay plus NAS product releases thereafter. The feature has been so successful it has lead QNAP and THECUS to offer the same in its product range as well. The more the merrier for all us consumers, a wider choice allows a better investment.

iSCSI is a bit of a dark horse and evades many as to what it is, how it works and what benefits can be derived from its deployment. When iSCSI was introduced to the mainstream SMB platform in and around 2004, many questions arose and comparisons were drawn in relation to its functionalities with the then successful and powerful Fibre Channel. This further accentuated uncertainty because FCIP is about taking Fibre Channel frames and sending them over an Internet Protocol (IP), basically extending a Fibre Channel connection, nothing really to do with SCSI at all. iFCP on the other hand is about mapping FCP (serial SCSI over Fibre Channel) into and out of Internet Protocol (IP).

So, what exactly is iSCSI? here is a definition of sorts that may help towards understanding.

What is iSCSI?

DEFINITION - iSCSI is Internet SCSI (Small Computer System Interface), an Internet Protocol (IP)-based storage networking standard for linking data storage facilities, developed by the Internet Engineering Task Force (IEFT). By carrying SCSI commands over IP networks, iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. The iSCSI protocol is among the key technologies expected to help bring about rapid development of the storage area network (SAN) market, by increasing the capabilities and performance of storage data transmission. Because of the ubiquity of IP networks, iSCSI can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet and can enable location-independent data storage and retrieval.

How iSCSI Works:

The technology is implemented by loading a software-based driver--called an initiator--on an Ethernet adapter or by adding a dedicated iSCSI host bus adapter (HBA) to the host. Another initiator is added to the target storage array, which allows it to serve up data that will be transported across the network via the iSCSI transport.

iSCSI initiators are available from a number of sources and are categorized by operating system type. Two of the most popular are a Windows initiator from Microsoft Corp. and a Linux initiator from SourceForge.

Target storage arrays are available from almost every vendor in our portfolio, including THECUS, QNAP and NETGEAR, among others.