FCoE considerations with virtualization: Support, SAN integration

Fibre Channel over Ethernet can improve network reliability, but not all vendors support FCoE, and it can be tricky integrating it with network switches and adapters.

Fibre Channel over Ethernet is a storage networking method that encapsulates Fibre Channel frames over Ethernet LANs. It essentially continues the use of Fibre Channel over 10 GbE Ethernet connections, preserving the advantages of the Fibre Channel protocol while eliminating the separate networking requirements.

One of the biggest benefits to storage networking with Fibre Channel over Ethernet (FCoE) in virtual infrastructures is improved network reliability. Ethernet generally drops or loses frames. This is harmless for regular Ethernet file transfers because lost frames are typically resent and reassembled in the correct order. But that doesn’t work so well for storage subsystems, and any form of network packet “loss” can disrupt storage and cause errors. FCoE is also purported to integrate seamlessly with existing Fibre Channel storage area networks and management software.

“Right now, FCoE is a graceful way to transition from a large Fibre Channel environment into an Ethernet one or to extend the life of the existing Fibre Channel infrastructure,” said Bob Laliberte, senior analyst with the Enterprise Strategy Group in Milford, Mass., noting the importance of preserving millions of dollars of storage networking infrastructure already in place.

FCoE adoption: Look before you leap
But Fibre Channel over Ethernet is still a new and fairly immature technology that does not simply stack on top of Ethernet like Internet SCSI does. Organizations considering an FCoE deployment need to upgrade server network adapters and switches to FCoE-compliant models. Proper deployment of FCoE demands a thorough understanding of Fibre Channel technology and management.

FCoE may not yet enjoy full support across the entire network infrastructure—not all vendors support Fibre Channel over Ethernet from the switch to the storage subsystem yet. Consider this: If you can’t support FCoE from end to end, it may be necessary to sustain support for Fibre Channel as well and merge the two technologies with bridges or gateways until end-to-end support can be deployed with emerging protocols such as FC-BB-6.

Still, this issue is likely to fade as FCoE adoption ramps up for storage networking in virtual infrastructures and more supporting products reach the marketplace.

“Be aware that everything isn’t there that you might have been used to from the Fibre Channel world,” said Greg Schulz, founder and senior analyst at StorageIO in Stillwater, Minn. “The interoperability isn’t all there yet. You’ve got the different vendor implementations of their switches [and] adapters, and they’re all working diligently to work through all those interoperability issues.”

Schulz urges thorough proof-of-principle testing and evaluation before making an investment in FCoE for storage networking.

It’s too early to see Fibre Channel over Ethernet trends that favor virtualization, but it’s clear that FCoE is positioned for growth and native support in new hardware. Schulz said new chipsets emerging for FCoE-compliant ports on servers support both Fibre Channel and Ethernet traffic on the same cable with less translation between both protocols with features like multi-route I/O virtualization. This should allow for lower hardware costs, more network consolidation and better performance for virtual servers in the data center.   

Stephen J. Bigelow, a senior technology editor in the Data Center and Virtualization Media Group at TechTarget Inc., has more than 20 years of technical writing experience in the PC/technology industry. He holds a bachelor of science in electrical engineering, along with CompTIA A+, Network+, Security+ and Server+ certifications and has written hundreds of articles and more than 15 feature books on computer troubleshooting, including Bigelow’s PC Hardware Desk Reference and Bigelow’s PC Hardware Annoyances. Contact him at sbigelow@techtarget.com.

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