The emerging Fibre Channel over Ethernet (FCoE) standard promises to bring back the good old days of the raging Fibre Channel vs. iSCSI debates. Or does it?
First, a little history. When the FCoE concept was first hatched about two years ago, naysayers -- and sometimes the press -- jumped all over it: FCoE was a "last ditch ploy" by Fibre Channel "bigots" to stem the "inevitable tide of Ethernet" taking over all types of data center traffic, including storage via the iSCSI protocol. The rhetoric ran rampant, but then it died down into more politically correct statements such as "Fibre Channel and iSCSI are complementary, not competitive."
I actually bought that for awhile, in part because I (and many others) didn't think that iSCSI would ever be considered for enterprise data centers (which is where FCoE would play). As such, iSCSI would eventually dominate at the departmental level and at SMBs while Fibre Channel, or FCoE, would dominate in data centers as companies moved to converged networks, or whatever you want to call them.
Then along came 10GbE (10Gbps Ethernet) which, once it gets cheaper, all of a sudden makes iSCSI seem feasible as the kingpin storage protocol for data centers. Then again, I don't see data-center managers (or at least the storage managers) giving up on all the Fibre Channel equipment, software, and expertise they've accumulated.
It does seem clear that data-center managers will eventually have to make a choice between FCoE and iSCSI, assuming they're moving to converged networks. Hence the controversy and all the early promotional activity from the FCoE camp.
Another possibility is that FCoE will be used as an interim "stepping stone" technology on the path to a true converged network with one physical layer transport for all traffic.
Yet another possibility: The real competitor for FCoE is not iSCSI but, rather, the status quo. In this scenario, data centers keep their Fibre Channel SANs for storage and their Ethernet LANs for everything else -- and never the twain shall meet.
Maybe I just have FCoE on the brain because of some of the company I kept at last week's Storage Networking World show -- which included Brocade, Emulex, and QLogic -- but in my next blog I'll look at some of the lingering questions/issues surrounding this nascent technology.
posted by: Dave Simpson