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 several factors.
“My company is in watch mode with iSCSI,” says John Blackman, system architect for Emerging Technologies & Consulting at Wells Fargo in Minneapolis, Minn. “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 cheaper and better.
“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.
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.
Gruener says also hampering sales is the current economic malaise and a risk-averse industry.
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. 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.
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 centre in midsize businesses or departments and branch offices in the corporation, where performance is not that crucial.
Despite the negativity, Gartner predicts the market for iSCSI adapters will increase from US$590 million this year to US$1.22 billion in 2005. IDC says the total iSCSI market will be double that figure or US$2.48 billion in 2005, almost a sixfold increase in compound annual growth.