subject: What Is Iscsi? [print this page] iSCSI is an abbreviation for Internet Small Computer System Interface. It is a storage networking standard for connecting data storage devices and facilities based on the model transmission control protocol/internet protocol. The iSCSI protocol allows for input/output operations and creates a network, e.g. Storage Area Network (SAN).
Storage area network is a network storage type where iSCSI technology is largely used. It so because iSCSI is very efficient in wide SAN system creation and reduces its costs when compared with other solutions, e.g. popular Fibre Channel technology. Unlike Fibre Channel, iSCSI does not require additional dedicated cabling but makes use existing network infrastructure for long distances connections. iSCSI can be used to transmit data over local area networks, wide area networks and the Internet. can enable location-independent data storage and retrieval.
The iSCSI protocol allows clients who become initiators to send SCSI commands to SCSI storage devices which become their targets on even most remote servers. This protocol, allows organizations to consolidate storage facilities into data center storage arrays while providing hosts with the illusion of locally-attached disks. A storage array using iSCSI usually provides variuos iSCSI targets for a number of clients. iSCSI initiators and targets prove their identity to each other using the CHAP protocol, which includes a mechanism to prevent simple cleartext passwords from appearing. However, the CHAP protocol is vulnerable to dictionary attacks, spoofing, or reflection attacks.
The rules for using CHAP protocol within iSCSI can prevent most of these attacks only when carefully implemented and used. The iSCSI has a default settings on port 3260. The connection can be realized with the whole net traffic, even via modem or wireless network and can be configured on a dedicated interface communicating via optic fiber. To achieve high reliability, MPIO (Multipath Input/Output) solutions involving multiplication of net routes are used in iSCSI.
Plenty of IT engineers consider iSCSI as very useful as it allows the users to build storage for a fraction of the cost they would need to pay for Fibre Channel technology. Users can buy an iSCSI NAS feature pack to serve block data as well as traditional file and print data from a single NAS head. On the Internet there are many instances of such iSCSI NAS product. QNAP has quite a list of relevant devices, supporting iSCSI along with the usual set of integrated features like webserver, iTunes serving, etc. With up to four 1TB disks, these products have so far proven excellent value for money.
