Who needs 4Gbps Fibre Channel?

By Sonia R. Lelii

Host bus adapter (HBA) and switch vendors are expected to usher in 4Gbps Fibre Channel products late this year or early next year, a move that will make 4Gbps an interim speed before the industry takes on the major forklift transition to 10Gbps Fibre Channel.

For example, this fall, QLogic plans to unveil a slew of 4Gbps chips and board-level products, including switches, HBAs, and controllers, while switch vendors like Brocade and McData plan to ship 4Gbps switches to OEMs and end users in the first half of next year.

The move to 4Gbps Fibre Channel, which under the covers is the same as 2Gbps but is twice as fast, is a transition technology that gives users more speed at approximately the same price points as 2Gbps products.

Frank Berry, vice president of marketing at QLogic, says that 2Gbps Fibre Channel currently costs about $800 per port.

"We expect the 4Gbps price point to be the same," says Berry.

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As for end-user adoption of 4Gbps Fibre Channel, it may largely depend on application requirements. It's estimated that a small user base will make a quick move to 4Gbps technology solely because they need more bandwidth, according to Rick Villars, vice president of storage systems at International Data Corp. (IDC).

"Less than 5% [of existing Fibre Channel users] will look at 4Gbps technology because they absolutely need the throughput. This is not going to drive this technology. [4Gbps] is not happening because customers are pushing for more horse-power. The manufacturers are driving this," says Villars.

In fact, up until about a year ago, the storage industry expected to swing from 2Gbps Fibre Channel directly to 10Gbps, with no interval speed in between. The SAN market was planning to follow the Ethernet market, which tends to increase speed tenfold each time a new version comes out. The idea was for storage networks and Ethernet networks to converge at 10Gbps so development costs could be reduced.

"It made a lot of sense, but there was a catch," says QLogic's Berry. The glitch came from the disk drive manufacturers. That part of the industry does not lend itself to tenfold speed increases each new generation. They generally double performance. But that did not stop companies like QLogic, which manufactures chips in addition to switches and HBAs, to consider the idea of making 4Gbps components as an interval step.

One key application that may make 4Gbps attractive is backup. IT storage managers are contending with shorter and shorter backup windows. Theoretically, 4Gbps goes twice as fast as 2Gbps, which implies a 2x performance increase for backups.

"From what I am hearing, 4Gbps may show up in tape drives first," says Jay Kidd, chief technology officer at Brocade.

Other users that could benefit from 4Gbps speeds are media production houses and cable providers that deal with real-time streaming video applications. For instance, Jim Farney, senior marketing manager for media industries at SGI, says 4Gbps will give a needed bandwidth boost in areas such as High Definition Video. Typically, HDV requires striping data across a pair of 2Gbps Fibre Channel connections in order to push data through at a suitable speed. A 4Gbps Fibre Channel connection would allow simpler configurations.

But some analysts say the rich media market has such an insatiable need for bandwidth that they have moved past the need for 4Gbps Fibre Channel. "Most [large studios] rely on proprietary environments," says IDC's Villars. "And some have already moved on to 10Gbps [Ethernet]."

Other users, especially those who don't have to contend with bandwidth issues, are not in much of a hurry to get 4Gbps products into their environments. Craig McNight, a Unix systems administrator at Northwestern University, says there are no plans in the works at the university to upgrade from its current 2Gbps Fibre Channel SAN to 4Gbps.

Northwestern has 150 to 200 servers, and many HBAs would have to be switched out if the university were to upgrade to 4Gbps Fibre Channel.

"We don't have a huge [bandwidth] issue," says McNight, "and there are a lot of [more important] projects going on."

Scott Blancett, a senior project manager in the IT department at Johns Manville, a manufacturer of insulation and roofing products, says his company has no immediate plans to move to 4Gbps Fibre Channel. "We might go to 4Gbps when the prices go down to 2Gbps prices. But will I rip out my entire infrastructure to go to 4Gbps? No. Will I even rip out my entire infrastructure to go to 10Gbps? No. It's all about the money," says Blancett.

Some vendors, however, are hoping for the "consumer effect" to help pull customers into upgrading to 4Gbps. "In other words, once customers get a 4Gbps component from one vendor then they want it from every vendor," says Peter Dougherty, vice president of switch operations at McData.

"Users want to feel comfortable that they're getting the 'latest and greatest,' " continues Dougherty. But he concedes that the new speed needs to be supported in hosts, switches, and targets before users can get the full performance benefit. This is because SAN components will "auto-negotiate" down to the speed of the slowest component on the link.

But there could be other, more-creative, uses for 4Gbps Fibre Channel. One is to use 4Gbps connections as inter-switch links (ISLs). (QLogic already offers 10Gbps ports for ISLs on some of its switches.)

"Users are not clamoring for [4Gbps]. It's an incremental improvement," says Scott Carson, chief technology officer and managing director of technical services at IMS Systems, in Silver Spring, MD. "But once it comes out, they will make effective use of it."

This article was originally published on July 01, 2004