Feature

IP SANs take their place

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One way or another, your enterprise storage is going to be networked. The question is how: Fibre Channel (FC) or Internet Protocol (IP)? Most likely, it will be both. Companies are starting to employ iSCSI at the edge for less critical or performance-intensive storage, and then using it or other IP protocols to connect to central FC storage area networks (SANs) across the wide area.

"The mixed environment--where servers and storage leverage iSCSI to get to Fibre Channel central storage--is becoming more popular," says Rick Villars, IDC vice president of storage systems.

Cisco Systems, which provides products for both IP and FC, concurs. "iSCSI fits in two places, as access technology to let departmental servers connect to corporate data center storage and to host storage right on an IP network using storage arrays running iSCSI," says Bill Erdman, director of marketing at Cisco's storage technology group.

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IP storage standards
iSCSI: an IP-capable version of SCSI for use as a storage networking standard
Fibre Channel over IP (FCIP): enables the transmission of FC data over an IP network through the use of tunneling
Internet Fibre Channel Protocol (iFCP): enables the transmission of data to and from FC devices using TCP/IP, which provides the necessary congestion control and error detection and recovery services

Until recently, a SAN meant FC networks. In February after approximately three years of deliberation, the Internet Engineering Task Force (IETF) approved the iSCSI specification, which is a protocol for block-level storage over IP. iSCSI will go a long way toward enabling IP-based SANs that can rival FC SANs, and it gives enterprises new SAN networking options. Already, midsized organizations such as Southern Insurance Underwriters, Mapics Inc. and Buckeye Color Labs are turning to IP to boost their storage networking.

Although "IP and iSCSI won't replace Fibre Channel," says Villars, it will provide greater flexibility in how storage is deployed.

Initially, he sees it being used as a way to extend or to connect SANs. IP will be particularly useful in remote backup scenarios in which storage must be replicated to remote sites. While this can be done with IP today, the availability of iSCSI will make it easier to use IP for block-level storage.

"With iSCSI, the pieces of the puzzle are all here. The iSCSI engine should get IP storage really moving," says Arun Taneja, consulting analyst for the Taneja Group, in Hopkinton, MA.

Initially, iSCSI will appeal to large companies with remote sites. "They will use iSCSI to consolidate backup from remote sites and smaller servers," Villars says. Midsized and smaller firms eventually will use IP and iSCSI to network and consolidate their storage. Many of these companies have steered clear of networked storage because of its cost and complexity. Adds Taneja: "iSCSI is a natural for small and midsize companies, workgroups and departments."

The impact of the ratification of the iSCSI specification was felt almost immediately. "It has pushed out more products. When we set up our iSCSI SAN, the only choice was Intel cards. Now there are others," says Robert Filipovich, IT manager at Southern Insurance Underwriters Inc., in Alpharetta, GA.

IBM now offers an iSCSI storage array--its TotalStorage 200i comes with up to 3.5TB of storage. EMC is planning to offer iSCSI in both its Symmetrix and Clariion storage products. Other vendors with iSCSI offerings include Adaptec, Alacritech, FalconStor, Hewlett-Packard, Network Appliance and more. The release of Windows Server 2003 with built-in iSCSI support should trigger a flood of new iSCSI products.

Southern Insurance Underwriters turned to products from San Diego-based StoneFly Networks and Nexsan, Woodland Hills, CA, to create an IP SAN with 2.2TB of capacity for a cost of about $30,000, plus the nominal expense of adding a few more gigabit copper ports to its switch chassis. The storage network was needed to handle the massive volume of insurance forms managed through the company's electronic document imaging system. In addition, the company found itself faced with storing rapidly growing amounts of e-mail.

Until it implemented the iSCSI SAN in January 2003, the company had been adding SCSI arrays to its database and Exchange 2000 servers. But the proliferating storage arrays were growing out of hand, driving the company to seek a centralized storage solution. A conventional FC SAN appeared to be the likely option, but "we wanted to avoid the costs and complexity associated with FC SAN solutions," Filipovich says. The company looked at network-attached storage (NAS), which provides file-level storage, but concluded "the NAS model gave us absolutely zero benefit in the application space." The company's applications required block-level storage.

This was first published in July 2003

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