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Wednesday, December 3, 2008
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FCoE

First, I would like to thank Douglas Gourlay for responding to my post at http://www.networkworld.com/community/node/24657/177203#comment-177203. You can find his home page at Cisco http://blogs.cisco.com/datacenter/ in his role as Senior Director of Marketing and Product Development for Cisco Data Centre.

All that Fibrechannel and FCOE adds to a data centre is more complexity, and more organisational pain. 'Operational Orchestration' does not occur. Fibrechannel enables the Server and Networking teams to balkanize and does not create synergy. Worse, it creates an opportunity to have a dialog about my FC is better than your IP.

I do not fondly remember the same debates when we had FDDI and Token Ring. And just change the word Token Ring for Fibrechannel and we are having exactly the same debate from 15 years ago. Have we learned so little ?

In data centers that use iSCSI as a primary method, and Fibrechannel as the "if we have to" storage works just fine.

I can understand the Fibrechannel over Ethernet (FCoE) is stateless, and IF THE UNDERLYING TRANSPORT is lossless you get a BIT more performance for some people. But FCoE is not an enabler for "Synchronous replication, storage media encryption, data migration, etc." thats a software feature that occurs above the transport layer, and can also be done using iSCSI and even FCIP.

If the iSCSI cost point is higher, lets compare that against the financial cost of implementing Fibrechannel at all. Fibrechannel anything costs a squillion bucks to buy, and two squillion bucks to support. So what if a bit of performance is lost with iSCSI, it costs a quarter of squillion to do.

You can certainly throw some of the cash you saved by NOT using Fibrechannel to applying 'buffers' or anything else that fix the problem such as buying more TOE cards. Even buying more servers is viable because of the monstrous power consumption of Fibrechannel chips and equipment.

On the latency 'thing'. If you need real time lossless connectivity, then just engineer the IP network to do that. Its easy enough to do, just because IP CAN drop packets, doesn't mean that it always does ? Can't software drivers be developed that stop buffering ?

(Aside: I remember a few years back that Cisco had the latent, store and forward, lossy 1.2Gb/s shared backplane Catalyst 5000 switch competing against the nonblocking Bay Networks 28000. Customers voted by buying the one that was cheaper)

Even now most servers cannot use the performance of fibrechannel anyway, and are not likely lift performance in the next five years to use it either. The X86 CPU/Memory bus architecture doesn't let data transfer that fast - witness the failure of 4GB fibrechannel except as a Fibrechannel switch interconnect technology.

(Note: bus architectures for other platforms exist, but, who cares ? X86 defines the data center market)

Lets face it, Fibrechannel is a poor mans Infiniband, and Infiniband is the real deal. Lets get over Fibrechannel and move on to the end game.

PS: The Cisco Nexus 7000 looks like a good ethernet switch for my data centre. I will be putting them into my strategy and it stops Foundry and Woven Systems from bothering me.

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