iSCSI good for agency storage ills

An industry association is touting the emerging iSCSI interface as a low-cost way for agencies to jump into networked storage.

Products using the Internet Small Computer System Interface standard will cost less than Fibre Channel-connected storage area networks, speakers said at a conference yesterday in McLean, Va., sponsored by the Storage Networking Industry Association.

Most government agencies have traditionally been more value-oriented than performance-oriented, said David Dale, chairman of SNIA's Internet Protocol Storage working group. Many agencies do not mind taking a slight performance hit if it saves money, he said. ISCSI SANs would be particularly appealing to agencies that lack network storage but nonetheless find themselves starting to manage terabytes of data, Dale said.

Vendors estimated that iSCSI has 80 percent as much speed as Fibre Channel at 20 percent of the cost.

SCSI connectivity has long been used to link a peripheral such as a hard drive to a computer. ISCSI encapsulates SCSI commands in IP data packets that can be sent to other computers, allowing them to store data over networked devices. (Click to link to Sept. 1, 2003, GCN story)

The standard for the interface became final last January, and Microsoft Corp. has introduced iSCSI software for its Windows Server 2003 operating system.

Robert Gray, an analyst at research firm IDC of Framingham, Mass., said iSCSI SANs are best at housing 5T to 20T, whereas Fibre Channel is more appropriate for storing 20T and up. Smaller organizations are overserved by Fibre Channel, Gray said. He predicted major storage vendors such as Hewlett-Packard Co. and EMC Corp. of Hopkinton, Mass., will introduce iSCSI offerings this year.

Fibre Channel has up to 2-Gbps throughput, faster than IP-based SANs, which now mostly use Gigabit Ethernet to carry traffic. But where iSCSI SANs trail in performance, they make up for it in price, other speakers said. ISCSI can use commodity hardware. Fibre Channel also uses IP to carry traffic, though hardware interoperability has traditionally been a problem. With iSCSI, 'IP switches have to work together,' said Henry Green, director of platform development for SAN storage provider Intransa Inc. of San Jose, Calif.

Intransa has calculated that a 16-node iSCSI SAN would cost $60 per switch port, compared with $950 per switch port for Fibre Channel. Network administrators already familiar with maintaining IP networks can quickly learn iSCSI SANs, Green said. Existing local or wide area networks can even carry SAN traffic, eliminating a separate storage network.

On the downside, tools for hacking into IP networks are far more common than those for disrupting Fibre Channel networks, and iSCSI SANs might be more vulnerable to intrusions.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.


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