Fibre Channel getting faster

With Emulex and QLogic last week airing plans for 8Gbps Fibre Channel products, storage-area networks are about to get faster. But customers we interviewed don’t sound too desperate for a speed boost over the 2G and 4Gbps Fibre Channel products they now use.

“While some very I/O-intensive supercomputing needs for 8Gbps Fibre Channel exist, most users’ SAN performance is not eclipsing the 2Gbps Fibre Channel they already own,” says Michael Passe, storage architect for Beth Israel Deaconess Medical Center in Boston. “Users are only moving to 4Gbps Fibre Channel because manufacturers are moving in that direction. The logical place for 8Gbps Fibre Channel is in the host virtualization space, where you have several virtual hosts vying for the same physical host bus adapter.”

Barry Strasnick, CIO for CitiStreet in North Quincy, Mass., says his organization has never come close to hitting constraints with 2Gbps Fibre Channel for financial services processing for the 12 million participants it serves.

“I know it may sound boring, but realistically the major I/O constraint for us is still ‘old-fashioned' disk spindle speed, which is handled by intelligently spreading the load over more spindles,” says Strasnick, who uses QLogic host bus adapters and Brocade switches in his SAN.

The new 8Gbps host bus adapters and switches, which will be available next year, will likely be used initially to link Fibre Channel segments together, enabling consolidation between storage devices and for applications such as backup and video post-production that require higher performance. They could also be used “to aggregate and allow more servers to attach to a given number of storage ports, to support virtual servers that may have aggregated performance needs and for inter-switch links where 4Gbps Fibre Channel is not cutting it yet today,” says Greg Schulz, senior analyst with StorageIO.

But at least some customers say that when they do replace their 2G or 4Gbps Fibre Channel infrastructures, they will likely do so with technologies such as iSCSI and 10Gbps Ethernet.

“I have no plans to go to 8Gbps Fibre Channel for the next three years,” says Ken Walters, senior director of enterprise platforms at the Public Broadcasting System in Alexandria, Va. Walters uses 4Gbps port modules in his McData Intrepid director-level switch to connect to 4Gbps McData or Brocade edge switches.

“When I replace this SAN, I will definitely look to iSCSI on 10Gbps Ethernet and hopefully copper Fibre Channel cabling instead of fiber optic,” says Walters. “If for some reason that is not workable but 8Gbps Fibre Channel is, then I would probably go with that.”

Neither does Beth Israel’s Passe have plans for 8Gbps Fibre Channel.

“We are still only using 4Gbps for connections to our newer arrays,” says Passe. “We probably will start to deploy iSCSI to support some specific applications and help with our disaster recovery plans in the coming two years. It would seem that the future of iSCSI with 10Gbps Ethernet is bright, although we don’t have 10Gbps Ethernet infrastructure in place here just yet; it will become more affordable and show up in the correct time frame.”