SANs Come Up to Speed
Outlook: Cost and backward-compatibility issues could delay acceptance of 10Gbit Fibre Channel in favor of two interim standards.
Computerworld - Storage networking equipment vendors are preparing a slew of new Fibre Channel switches and host bus adapters that can effectively double the speed of current storage-area networks (SAN) to 4Gbit/sec. Products based on the 4Gbit standard, first advocated by chip makers last year and approved by the Fibre Channel Industry Association (FCIA) and the American National Standards Institute last June, are slated to roll out this year. The technology could serve as an interim migration step to products based on the 10Gbit/sec. Fibre Channel specification approved by the FCIA last November.
But not all users are convinced that more speed is better, especially where application servers are the bottleneck. "On the fabric side, it's screaming . . . but you'd saturate your [server] bus long before you'd saturate a 1Gbit or 2Gbit Fibre Channel connection," says Gary Pilafas, senior storage and systems architect at UAL Loyalty Services Inc., an Arlington Heights, Ill.-based unit of United Air Lines Inc.
Mike Bennett, a senior network engineer at Lawrence Berkeley National Laboratory in Berkeley, Calif., believes that new servers being offered with 64-bit processors and faster internal bus designs will require more than the additional bandwidth being offered by 4Gbit Fibre Channel switches, RAID controllers and host bus adapters for SANs.
"Two years out, is there going to be a market for it? I'd say no doubt. It's like garage space: If you have it, you'll fill it," Bennett says.
By that time, however, 4Gbit products will face competition from devices based on a faster 10Gbit standard. In fact, as vendors begin volume shipments of 4Gbit products this summer, they'll be introducing early 10Gbit products as well.
Bennett says 10Gbit Ethernet will challenge Fibre Channel as an alternative storage interconnect if Fibre Channel doesn't keep up, so a leap to 10Gbit is a must. But 4Gbit devices offer critical advantages: Analysts and vendors say the 10Gbit/sec. devices won't be backward compatible with current 1Gbit or 2Gbit products. And they're expected to cost about $5,000 per portfive times as much as current 2Gbit devices.
In contrast, the upcoming 4Gbit devices are expected to cost about $1,000 per port, the same as their 2Gbit cousins.
As a result, analyst Rick Villars at market research company IDC in Framingham, Mass., is bullish on the standard's prospects. He predicts that 4Gbit products will hit the market in the third quarter but account for just 10% of the market within the first 12 months. After two years, however, he expects that number to leap to 90% as competitively priced 4Gbit products replace slower offerings.
"They're going to be the best technology at the lowest price," Villars says.
Meanwhile, high prices and backward-compatibility concerns will limit the appeal of next-generation 10Gbit devices. "You have to replace anything that the 10Gbit technology touches with all-new 10Gbit equipment," says Villars.
The Third Option
Aware of these limitations, vendors came forward with the interim 4Gbit standard. And hedging their bets yet again, SAN equipment vendors have another interim Fibre Channel standard in the offing. Disk drive manufacturers are rallying around a newly proposed 8Gbit specification, and SAN managers could see products within three years, according to manufacturers.
Skip Jones, chairman of the FCIA's Speed Forum, says the organization held its first meeting on 8Gbit Fibre Channel last month. "If we get out there three years, and you're still paying a huge premium for 10Gbit technology and you want that backward compatibility, that's where 8Gbit will be attractive," he says.
For now, the focus is on 4Gbit products. Several vendors, including San Jose-based Hitachi Global Storage Technologies Inc., the disk manufacturing arm of Hitachi Data Systems Inc. (HDS), have announced 4Gbit Fibre Channel offerings (see box at right).
So where does that leave 10Gbit Fibre Channel? Despite the cost and compatibility issues, vendors see a place for the developing standard in high-end SANs. Hubert Yoshida, chief technology officer at HDS, says 10Gbit products will serve as an interswitch link that can cobble together many switches in a SAN fabric while using fewer ports. He also sees it as a way to create many virtual ports over one physical switch port. "Through the same physical port, we can allow up to 128 different users," he says.
Arun Taneja, an analyst at The Taneja Group in Hopkinton, Mass., predicts that the demand for 10Gbit Fibre Channel will be enormous, both for connecting internal disk drives to RAID controllers and for interswitch links in corporate SANs.
"There's no large enterprise I know of in the Fortune 300 or 400 range that doesn't have a massive number of Fibre Channel switches at this point in time. As they replace those switches or directors with 4Gbit Fibre Channel ports, there's no question they'll need multiple 10Gbit ports to balance that out," Taneja says.