Why Open-FCoE is important

FCoE Frame Format (from Wikipedia, http://en.wikipedia.org/wiki/File:Ff.jpg)

FCoE Frame Format (from Wikipedia, http://en.wikipedia.org/wiki/File:Ff.jpg)

I don’t know much about O/S drivers but I do know lots about storage interfaces. One thing that’s apparent from yesterday’s announcement from Intel is that Fibre Channel over Ethernet (FCoE) has taken another big leap forward.

Chad Sakac’s chart of FC vs. Ethernet target unit shipments (meaning, storage interface types, I think) clearly indicate a transition to ethernet is taking place in the storage industry today. Of course Ethernet targets can be used for NFS, CIFS, Object storage, iSCSI and FCoE so this doesn’t necessarily mean that FCoE is winning the game, just yet.

WikiBon did a great post on FCoE market dynamics as well.

The advantage of FC, and iSCSI for that matter, is that every server, every OS, and just about every storage vendor in the world supports them. Also there are plethera of economical, fabric switches available from multiple vendors that can support multi-port switching with high bandwidth. And there many support matrixes, identifying server-HBAs, O/S drivers for those HBA’s and compatible storage products to insure compatibility. So there is no real problem (other than wading thru the support matrixes) to implementing either one of these storage protocols.

Enter Open-FCoE, the upstart

What’s missing from 10GBE FCoE is perhaps a really cheap solution, one that was universally available, using commodity parts and could be had for next to nothing. The new Open-FCoE drivers together with the Intels x520 10GBE NIC has the potential to answer that need.

But what is it? Essentially Intel’s Open-FCoE is an O/S driver for Windows and Linux and a 10GBE NIC hardware from Intel. It’s unclear whether Intel’s Open-FCoE driver is a derivative of the Open-FCoe.org’s Linux driver or not but either driver works to perform some of the FCoE specialized functions in software rather than hardware as done by CNA cards available from other vendors. Using server processing MIPS rather than ASIC processing capabilities should make FCoE adoption in the long run, even cheaper.

What about performance?

The proof of this will be in benchmark results but it’s quite possible to be a non-issue. Especially, if there is not a lot of extra processing involved in a FCoE transaction. For example, if Open-FCoE only takes let’s say 2-5% of server MIPS and bandwidth to perform the added FCoE frame processing then this might be in the noise for most standalone servers and would showup only minimally in storage benchmarks (which always use big, standalone servers).

Yes, but what about virtualization?

However real world, virtualized servers is another matter. I believe that virtualized servers generally demand more intensive I/O activity anyway and as one creates 5-10 VMs, ESX server, it’s almost guaranteed to have 5-10X the I/O happening. If each standalone VM requires 2-5% of a standalone processor to perform Open-FCoE processing, then it could easily represent 5-7 X 2-5% on a 10VM ESX server (assumes some optimization for virtualization, if virtualization degrades driver processing, it could be much worse), which would represent a serious burden.

Now these numbers are just guesses on my part but there is some price to pay for using host server MIPs for every FCoE frame and it does multiply for use with virtualized servers, that much I can guarantee you.

But the (storage) world is better now

Nonetheless, I must applaud Intel’s Open-FCoE thrust as it can open up a whole new potential market space that today’s CNAs maybe couldn’t touch. If it does that, it introduces low-end systems to the advantages of FCoE then as they grow moving their environments to real CNAs should be a relatively painless transition. And this is where the real advantage lies, getting smaller data centers on the right path early in life will make any subsequent adoption of hardware accelerated capabilities much easier.

But is it really open?

One problem I am having with the Intel announcement is the lack of other NIC vendors jumping in. In my mind, it can’t really be “open” until any 10GBE NIC can support it.

Which brings us back to Open-FCoE.org. I checked their website and could see no listing for a Windows driver and there was no NIC compatibility list. So, I am guessing their work has nothing to do with Intel’s driver, at least as presently defined – too bad

However, when Open-FCoE is really supported by any 10GB NIC, then the economies of scale can take off and it could really represent a low-end cost point for storage infrastructure.

Unclear to me what Intel has special in their x520 NIC to support Open-FCoE (maybe some TOE H/W with other special sauce) but anything special needs to be defined and standardized to allow broader adoption by other Vendors. Then and only then will Open-FCoE reach it’s full potential.

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So great for Intel, but it could be even better if a standardized definition of an “Open-FCoE NIC” were available, so other NIC manufacturers could readily adopt it.

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