It sounds like a good idea. Technology that makes it possible to build less expensive, native IP-based storage networks and mixed Fibre Channel-to-IP storage-area networks.
But in practice, network executives are adopting IP storage (iSCSI) at a slow pace. Analysts say that the users who are interested in deploying iSCSI, which uses TCP/IP to transport block-level data over Gigabit Ethernet, are deterred by:
-- The lack of native array support from EMC Corp., Hitachi Ltd., IBM Corp. or Hewlett-Packard Co.
-- An industry that is risk-adverse to any new technology because of the economy.
-- Interoperability concerns caused by TCP Offload Engines (TOE).
-- Concerns that iSCSI could be replaced by other faster, less-expensive technologies such as 10G Ethernet or InfiniBand.
"I don't think there has been any [iSCSI] adoption," says Tony Prigmore, senior analyst with Enterprise Storage Group Inc. "IBM (Corp.), for instance, pulled the plug on the only iSCSI array in the business, so at this point there is very little iSCSI installed."
While users say iSCSI is attractive because it should be able to be installed and configured like Gigabit Ethernet and is less expensive than the more complex Fibre Channel, they have concerns.
"My company is in watch mode with iSCSI," says John Blackman, system architect for Emerging Technologies & Consulting at Wells Fargo in Minneapolis. "With iSCSI, we are concerned with not only the fact that no major storage vendor has iSCSI storage arrays, but with routing issues, pricing and performance."
Blackman says the SCSI Remote Protocol (SRP) over InfiniBand could replace iSCSI and do it less expensively and with better performance.
"I don't know what the life of iSCSI will be - part of it is because iSCSI needs a dedicated Ethernet network," he says. "If I look at my servers, I have dual adapters for my data network, one adapter for management and another adapter for iSCSI. If I want fail-over or load-balancing [capability for iSCSI], I need to add another adapter. Plus, if SRP over InfiniBand at 30G bit/sec is available in 2003, I don't know what the impact of iSCSI will be."
Analysts recommend that users should wait to adopt iSCSI until more large storage vendors offer products.
"A lot of customers that would deploy iSCSI are waiting until 2003 for second-generation products and for more robust support from the storage vendors ," says Jamie Gruener, an analyst with The Yankee Group.
"If you look at the large storage vendors other than IBM, most of them have been pretty quiet so far. That's going to change in the second half of this year," Gruener adds.
Hitachi has said that it will support iSCSI in its Freedom Lightning 9900 array; HP is expected to make IP storage announcements later this year; and EMC has only said it will introduce iSCSI products when standards are available.
Further, Gruener predicts that a number of vendors are going to fail or never deliver products.
"There are going to be a number of failures because the market of volume [or demand] won't be there for the next couple of years," Gruener says. "There are so many companies vying for so little customer adoption in the short term."
Already, several companies have failed to get off the ground or decided to get out of the iSCSI business.
Two iSCSI start-ups, Entrada and NetConvergence, have shuttered their doors and 3Ware, the first company with an iSCSI array, recently reorganized its business around disk controllers.
IBM's venture with the TotalStorage IP Storage 200i has been uneventful. Even though IBM insists that it is still actively selling the TotalStorage IP Storage 200i, numerous calls to the company's online e-business site, IBM Direct, indicated that the product is at best hard to come by.
Gruener says another issue hampering iSCSI sales is the current economic malaise.
"All emerging technologies are facing the same general problems of customers are really cautious about deploying new technology in this economic downturn," Gruener says. "They are risk-averse."
Withstanding these disadvantages, present iSCSI adapters, called TOEs because they off-load the TCP/IP stack onto silicon on the card, suffer from routing problems. In off-loading TCP/IP from the operating system where it typically runs, the iSCSI adapter can't be used to handle alternate paths or load balancing with Gigabit Ethernet adapters co-residing in a server. They also can't be assigned to the same Windows NT domain as the Gigabit Ethernet adapter, where they can be managed more easily.
Vendors such as Intel and Adaptec, which are shipping off-loaded TCP/IP iSCSI adapters, say they will fix the problem before year-end. Alacritech, which shuttles the TCP portion of the stack between the operating system and the card, does not see the problems with routing the other adapters do.
ISCSI performance issues raise another flag for users. The technology, which is intended to give gigabit speeds, suffers in some implementations. Intel's Pro/1000 T IP Storage Adapter performs at 300M to 700M bit/sec, according to Intel, much less than that of 2G bit/sec Fibre Channel, 10G Ethernet or InfiniBand adapters. Adaptec and Alacritech say their adapters operate at wire speed.
Cisco, which markets the SN 5420 router and SN 5428 switch, says performance is not an issue for its products because they will be used outside the data center in midsize businesses or departments and branch offices in the corporation, where performance is not that crucial. Nishan Systems recently demonstrated wire speed performance with its IPS 3000.
Another issue that could affect user iSCSI adoption is the current lack of standards for the emerging protocol.
Standards not a concern
"For our implementation, standards weren't much of a concern," says Dave Mucha, Webmaster for construction machinery company Komatsu America International in Mundelein, Ill.
"The way Cisco has it set up is if something changes we just download another version of the software," Mucha says. "It takes only minutes to upgrade. The hardware stays the same."
He uses two redundant Cisco 5420 routers to attach his Web servers to IBM Enterprise Storage Servers.
With iSCSI, updates to the current release of the specification occur in software, requiring only a download of new programs.
A range of draft specifications for iSCSI management, naming, security and the protocol have been submitted to the Internet Engineering Task Force and are pending standardization. Among the drafts in "last call" status - one of the last steps before standardization - are the IP Storage Security, Storage Name Service and the iSCSI protocol specification.
A source close to the standards process said the iSCSI specification should be set by fall.
Despite the negativity, Gartner predicts the market for iSCSI adapters will increase from US$590 million this year to $1.22 billion in 2005. IDC says the total iSCSI market will be double that figure or $2.48 billion in 2005, almost a sixfold increase in compound annual growth.