4Gb--ready or not, here it comes

You might not need them, but 4Gb/sec Fibre Channel products are coming. Comparably priced to 2Gb/sec and backward compatible, they might end up in your storage network whether you need them or not.

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Next year, 4Gb/sec Fibre Channel (FC) products will start to roll out. These products will double the performance of 2Gb/sec gear for the same price, although the earliest adopters will probably pay a small premium until the full economies of large-scale chip production kick in.

Although the buzz about 4Gb/sec FC has been spreading for several months, no IT users have yet had a chance to test the technology, which is still working its way through the storage vendors' engineering labs. "There is nothing available yet, and nobody is screaming for it," says Tony Asaro, senior analyst, Enterprise Strategy Group, Milford, MA. Asaro, along with most industry analysts, has yet to see the technology demonstrated.

When it does arrive, 4Gb/sec FC's adoption should be a gradual, relatively painless process. IT managers may see little need for doubling FC performance now, but they should figure it into their plans as they consider refreshing their storage area network (SAN) technology in the future.

Fibre Channel roadmap

Performance improvement
The 4Gb/sec FC transition is the latest step in the inexorable improvement of performance, the FC equivalent of Moore's Law. FC networks have progressed from 1Gb/sec to 2Gb/sec, the current state of the art. Unlike the 10Gb/sec FC standard, which isn't backward compatible, new 4Gb/sec products will be completely backward (plug) compatible with 2Gb/sec and 1Gb/sec products, explains Skip Jones, chairman of the Fibre Channel Industry Association's (FCIA) speed forum and roadmap committee.

Backward compatibility will allow organizations to add 4Gb/sec products to environments still running older 1Gb/sec and 2Gb/sec devices without having to make any adjustments. "The 4Gb/sec products will autosense whether they are connecting with 2Gb/sec or 1Gb/sec products and ratchet down their speed to correspond," explains Charlie Kraus, director of marketing at LSI Logic Corp.'s host bus adapter (HBA) division. The same thing happened when the industry moved from 1Gb/sec to 2Gb/sec. Backward compatibility and autosensing ensured a gradual transition.

The 4Gb/sec action, however, isn't expected to heat up until 2005, although a few products might show up this year. At this point, "no products are shipping," says Richard Villars, vice president, storage systems at IDC, Framingham, MA. Instead, chips and test kits are going out to storage vendors for compatibility and interoperability testing. IDC expects it will take two years after products start shipping in 2005 for 4Gb/sec technology to reach 90% penetration.

Users haven't been clamoring for 4Gb/sec; the transition is being driven by the vendors' need to continue delivering improved price performance. "Disks don't saturate 2Gb/sec now, but they will eventually. The vendors need to have some headroom," says Kraus.

How 4Gb/sec FC can help
Although most users aren't demanding faster Fibre Channel, in certain situations, the benefits of 4Gb/sec may be realized now. For example, 4Gb/sec can ...
  • Eliminate dual trunking of 2Gb/sec connections
  • Speed storage performance for digital media
  • Consolidate high numbers of hosts
  • Reduce the need to buy more switch ports
User view
From a user perspective, the rollout of 4Gb/sec FC may turn into a non-event. Few have saturated their 1Gb/sec FC links, let alone their 2Gb/sec links. "We're running 1Gb/sec now and haven't been hampered at all," says Jay Chalfant, supervisor of PC and network support at Questa College, San Luis Obispo, CA. He's hoping to jump to 2Gb/sec at a significant discount when new 4Gb/sec products come out in volume next year. "I expect the price for 2Gb/sec products will drop at that point," he says. Of course, 2Gb/sec products will eventually disappear as vendors shift production to 4Gb/sec products.

"We push really big files through and we're not even taxing our 1Gb/sec link," says Todd Thomas, CIO, Austin Radiological Association, Austin, TX, which does medical imaging. He recently upgraded his 25TB SAN with 53 hosts, an EMC Symmetrix DMX1000 and two EMC Centera arrays attached. That required talking to a lot of vendors and "nobody even mentioned 4Gb/sec," he adds.

Likely early adopters
Maybe a company "that's trunking multiple 2Gb/sec lines today to get more bandwidth will really want 4Gb/sec," says FCIA's Jones, but he couldn't immediately recall any such companies. The vendors think that if they build it, price it comparable to 2Gb/sec products, and ensure backward compatibility and interoperability, the customers will come. "There is really no decision for IT managers to make. They will get 4Gb/sec when they buy new products," Jones concludes.

Early adopters are more likely to be video production firms than corporate IT. "We use an FC switch with our NAS, and have a mix of 1Gb/sec and 2Gb/sec links. We don't have a bottleneck with FC, but we always get the newest, fastest technology," says Maciek Maciak, chief engineer at Charlex, a New York digital video production house. Charlex uses dual 2Gb/sec FC links to connect its Silicon Graphics workstations directly to storage. "With 4Gb/sec FC, we might need just one," Maciak suggests.

Even at large enterprises, few IT managers see a need for 4Gb/sec other than for digital media. "Unless someone wants it for video editing, 4Gb/sec isn't something we absolutely need," says Richard Kruszewski, network administrator at TBWA/Chiat/Day, an advertising agency based in Los Angeles. To date, no one has expressed dissatisfaction with performance. "For us, 2Gb/sec is more than adequate," he adds.

Future opportunities
That's not to say that users won't want the extra performance in the future, especially if it costs roughly the same. History suggests that users eventually take advantage of performance increases and are soon looking for even more. "Customers are always asking us for continued improvements in FC products. Improvements in speed ultimately result in improved productivity, and 4Gb/sec is simply another speed improvement," says Doug Pickford, director of server market and product strategy at Hitachi Global Storage Technologies.

One possible use for 4Gb/sec, suggests ESG's Asaro, will be storage consolidation. For example, a company may need to virtualize and consolidate dozens or even hundreds of hosts at the FC port level. "This has the potential to overtax today's bandwidth. With 4Gb/sec FC, you wouldn't saturate the pipe," he explains.

It may also save organizations from buying more switches and ports. "Today, we get 3:1 servers to ports. With 4Gb/sec, we could get 6:1 or even 10:1," says Asaro. That could reduce the need to buy more ports.

The road ahead
The transition to 4Gb/sec FC is just the latest milestone on the FC roadmap. Next up is 8Gb/sec FC, expected in the 2007 to 2008 timeframe. From there, the picture gets a little cloudy. There is 10Gb/sec FC already, which uses a different fiber and is used mainly for interswitch linking. It doesn't provide backward compatibility, so it would require an entire forklift upgrade.

Others have suggested 12Gb/sec as the next step beyond 8Gb/sec, but that seems unlikely. Given the electronics science involved, "if you are not doubling, the technical challenge gets strange. Doubling is always better from an electronics standpoint," says FCIA's Jones. If nothing unforeseen pops up in the meantime, 16Gb/sec would roll out around 2010 to 2011.

Some users may simply skip 4Gb/sec. "We are fine with 2Gb/sec. We are nowhere near saturating it. We may ignore 4Gb/sec and go to 8Gb/sec when it comes out," says Joe Comeau, information systems manager at the University of British Columbia, Vancouver.

Whether you plan to go to 4Gb/sec FC or not, you're likely to get it anyway when vendors switch over to 4Gb/sec technology and discontinue their older products. With no price penalty, and with backward compatibility and interoperability assured, you might not even notice you've made the change.

This was first published in November 2004
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