Monday, September 26, 2011

#FCOE funny math

Check out this blog post from Cisco.

http://blogs.cisco.com/datacenter/3-for-2-the-fcoe-bandwidth-bonus/

It suggest that FCOE gives 50% greater bandwidth than 8gb FC.  While...theoretically true..its not in practice.

Here's why not..simple..not a long argument.  While I can transit FCOE at 10gb between server across a FCOE network... at the other end I can only hook up to 8gb FC compliant storage.  So..even if FCOE is more efficient and has more bandwidth, I can only talk to the end devices at 8gb.  This is especially true because FC is all about token credits..you can only send to me what I allow you to.  And...you cant buffer.  End result... no more throughput than your storage system has.

16gb FC is the next generation.  There are no converged adapters for 16gb FC yet.  So..for now that means 16gb FC is faster than 10gb FCOE.

Hence the problem with FCOE... its always going to be this disjointed architecture.

ISCSI today supports 10gb ethernet... it can utilize multi LAG 10gb...it can utilize 40gb.  It scales and it doesnt have the issues that FCOE has.

No comments:

Post a Comment