BY DAVE SIMPSON
As evidence of the growing interest in IP-based SANs, the Storage Networking Industry Association (SNIA) recently formed a group to market and promote emerging standards such as iSCSI.
The SNIA IP Storage Forum will work with the Internet Engineering Task Force (IETF) and other organizations that are developing IP Storage standards.
"This is a major step forward for IP storage, because the industry is coalescing around common goals," says Tom Clark, a member of the SNIA board of directors and director of technical marketing at Nishan Systems.
At a meeting last month, the SNIA IP Storage Forum elected officers, including co-chairs Doug Ingraham (Cisco) and Paul Mattson (IBM), and secretary Bill Lynn (Adaptec). More than 20 vendors participated. Direct involvement in the IP Storage forum is limited to SNIA members, but the forum plans to involve end-user organizations via special events, education seminars, and technology demonstrations. For more in-formation, send queries to email@example.com or visit the group's Website at www.snia.org.
The SNIA IP Storage Forum will promote all specifications that deal with block-level (as opposed to file-level) SCSI data transfers over standard IP networks such as Gigabit Ethernet. Those proposals include the iSCSI specification-championed by Cisco, IBM, and others-which maps the SCSI protocol to IP. The iSCSI standard is expected to be finalized by year-end. A first draft, which addresses SCSI mapping to IP and issues such as error handling and discovery, is expected by mid-year.
"iSCSI is an attempt to provide a single homogeneous technology, where IP is the only network that end users see," says Clod Barrera, director of strategy at IBM and an SNIA board member.
Basically, iSCSI intercepts a SCSI stream from an initiator, converts the stream to IP packets, transmits the packets over a TCP/IP network, and converts the packets back to a SCSI stream.
The SNIA forum will also promote specifications such as the Fibre Channel over IP tunneling spec and, if approved, various protocol submissions from vendors such as Nishan (see sidebar).
Most IT managers understand the potential advantages of IP SANs, which could eventually provide an alternative to Fibre Channel, but the real question is, When? Industry analysts aren't holding their breath. "IP SANs will not be implemented in production data centers within the next two years," predicts Steve Duplessie, senior analyst with the Enter-prise Storage Group.
Other analysts are somewhat more optimistic. "End users will probably be able to build pilot IP SANs in their labs in the third quarter, but it's questionable if they'll want to put them into production this year," says John Webster, a senior analyst at Illuminata.
A consensus of vendors and analysts predicts that IP SAN activity this year will focus primarily on standardization of technologies for running Fibre Channel traffic over IP WANs. They predict that focus will shift to iSCSI-based SANs in 2002.
Gating factors to widespread deployment of IP SANs include finalization of the iSCSI standard(s), development of high-speed host adapters that offload protocol stack processing from host CPUs, security issues, and availability of iSCSI device drivers and management software.
Despite the hurdles, few storage vendors doubt the eventual acceptance of IP SANs. In addition to heavyweights such as Cisco and IBM, even Fibre Channel-centric vendors have pledged eventual support. For example, at last month's SAN Solutions conference, officials from Fibre Channel switch leader Brocade Communications and adapter vendor QLogic both stated their intention to be players in the iSCSI market. And last month, QLogic acquired Little Mountain Group (LMG), a developer of iSCSI technology-including TCP/IP hardware accelerators-for use in adapters and storage controllers.
However, for IT managers, the ad-vice from consultants and analysts is consistent: If you need to build a SAN, start today with Fibre Channel. "IT managers have to network their storage now. NAS [network-attached storage] is great, but if you require block-level transfers you have to go with Fibre Channel," advises Duplessie. (NAS is based on file-level data transfers.)
Nevertheless, for some IT shops, "pre-iSCSI" SAN implementations may be an inexpensive way to implement a storage network. Vendors such as 3ware and Nishan are already shipping products that enable IP-based SANs with block-level I/O. 3ware, for example, recently began shipments of a RAID array that attaches directly to TCP/IP LANs (see InfoStor, December 2000, p. 10).
Nishan earlier this month announced an IP Storage gateway, switches that support IP and SCSI or Fibre Channel, and management software for IP Storage fabrics. Nishan claims to have more than a dozen IP SAN pilots up and running at end-user sites, based on its Storage over IP (SoIP) technology. Both 3ware and Nishan say their products will be compatible with the iSCSI standard when it's finalized.
And Cisco is expected to ship storage networking devices that will be iSCSI-compliant by mid-year. Those products are the result of Cisco's acquisition of NuSpeed last year (see InfoStor, September 2000, p. 1).
Multi-vendor demonstrations of iSCSI SANs are expected at this fall's Networld+Interop show. Analysts predict that IP SANs will be rolled out in phases, starting with small non-standard IP SANs and culminating in storage networks with native Gigabit Ethernet storage devices and protocol stacks.