Published on Nov 21, 2015
With the release of the Fibre Channel and SAN based on it the storage world staked on a network access to storage devices. Almost everyone announced that the future belonged to the storage area networks.
For several years the FC interface was the only standard for such networks but today many realize that it's not so. The SAN based on the FC has some disadvantages, which are the price and difficulties of access to remote devices. At present there are some initiatives which are being standardized; they are meant to solve or diminish the problems. The most interesting of them is iSCSI.
Several factors are rapidly expanding worldwide storage requirements:
" A pervasive global economy
Over the past decade, many enterprises have seen a significant increase in the volume of data produced. The amount of data continues to increase, particularly in Web-based and e-Commerce environments. E-mail impacts worldwide storage by producing more data than is generated by new Web pages. These types of traffic are typically multimedia intensive.
E-mail and Internet-related business/commercial transactions combined have caused a dramatic increase in storable data moving across Internet Protocol (IP) networks. This traffic can potentially overwhelm existing backup methods. A new method is needed to bring improved storage capabilities to IP networks and reduce limitations associated with Fibre Channel SANs. A rapidly emerging technology solution is Internet SCSI (iSCSI) or SCSI over IP.
Internet SCSI (iSCSI) is a draft standard protocol for encapsulating SCSI command into TCP/IP packets and enabling I/O block data transport over IP networks. iSCSI can be used to build IP-based SANs. The simple, yet powerful technology can help provide a high-speed, low-cost, long-distance storage solution for Web sites, service providers, enterprises and other organizations. An iSCSI HBA, or storage NIC, connects storage resources over Ethernet. As a result, core transport layers can be managed using existing network management applications.
High-level management activities of the iSCSI protocol - such as permissions, device information and configuration - can easily be layered over or built into these applications. For this reason, the deployment of interoperable, robust enterprise management solutions for iSCSI devices is expected to occur quickly. First-generation iSCSI HBA performance is expected to be well suited for the workgroup or departmental storage requirements of medium- and large-sized businesses. The expected availability of TCP/IP Offload Engines in 2002 will significantly improve the performance of iSCSI products. Performance comparable to Fibre Channel is expected when vendors begin shipping 10 Gigabit Ethernet iSCSI products in 2003.
The emerging iSCSI protocol specifies a method for encapsulating SCSI commands in the TCP/IP protocol - the messaging protocol of the Internet. This encapsulation means that the Internet, or any TCP/IP network, can be used to carry storage traffic.