I think almost every storage professional saw the news around the proposed FCoE standard.
If you missed it, simply google "FCoE ethernet" and there'll be plenty of reading for you. Or read this.
What's going on here?
And why does this proposed standard offer hopes for the stalled iSCSI marketplace?
Let's take a look ...
The Ups and Downs of iSCSI
Most storage people have seen the potential benefits of using Ethernet infrastructure for storage connectivity. It's not a new discussion.
At a macro level, ethernet components have an order-of-magnitude advantage in terms of economic scale as compared to FC components. As an example, think how much you pay for a FC host bust adaptor, vs. a decent ethernet NIC. Or a switch port.
Going a bit farther out, there's the hope of common infrastructure, common management and common services on some sort of converged data center fabric.
Well, that's the hope anyway.
And the industry's first try -- iSCSI -- only achieved partial success. The good news is that everyone ended up supporting it (including a few OS heavyweights like Microsoft who actually drove adoption).
And iSCSI has found a nice market home in new, smaller SANs where no FC is present.
Yet, at the same time, compared to the aggregate storage market, it's still a very small fragment. Proponents pointed to fast iSCSI growth rates, but -- according to IDC -- that's slowed as well.
And if you work in large enterprises that have made investments in FC infrastructure, you've probably noticed that they're just not interested in talking about iSCSI -- period.
I've written about the ups and downs of iSCSI before -- and gotten flamed in the process.
So, is FCoE going to be better than iSCSI? Will it enjoy broader success?
Too soon to tell, but the potential is tantalizing.
The Problem with TCP/IP (for storage guys, anyway)
Now, I'm not a deep technologist, I just pretend from time to time, but let me wade in here.
One core issue with iSCSI appears to be that it uses IP transport protocols.
Yes, this means that traffic is routable, and IP network guys can set up SANs and the IP ecosystem generally works.
But it also inherits some of the problems of the IP stack.
As an example, FC is lossless, and offers near-guaranteed latency. No such guarantees with IP stacks. If you're a big shop with performance and predictability concerns, that's an issue.
iSCSI manages like an IP network. Which means it doesn't manage like a FC SAN. Which means if you build and manage FC SANs, that's an issue for you.
And there are significant parts of the extended FC SAN feature set that never really made it into the iSCSI world. Generally speaking, these are the features that larger enterprise customers want.
And I don't want to wade into performance debates, but adding an IP protocol layer that the FC use case sees as mostly useless overhead is an issue as well.
Put it all together, and enterprise storage guys had plenty of reasons to pass on iSCSI in larger shops.
Fibre Channel over Ethernet -- in its simplest form -- tries to rectify some of these concerns.
First, there's a direct one-to-one mapping of FC frame to Ethernet frame. No IP protocols. No extra stuff. As close to a bare-metal protocol as you're likely to see. This means fast and simple.
Second, there are extended mechanisms (as part of the proposed standard) to guarantee latency without retry -- that's the "pause" mechanism you read about. FC does that, FCoE mimics this behavior.
Third, the design point is that it is designed to look, smell, behave, manage, etc. as an FC network that just happens to use Ethernet as its base protocol. It doesn't try to get too fancy.
There's more stuff in there that I thought I saw (congestion management, creating "hard" subchannels for different kinds of traffic, and so on) which all looks cool, but is more like frosting on the cake [more on that in a subsequent post]
But at its simplest level, it's a straightforward attempt to bring the economics of Ethernet hardware (in this case 10gE) to the enormous world of FC SANs by not trying to do too much.
Simple is good.
What Does This Mean?
So, a bit of a reality check.
- There are no FCoE products in the marketplace today.
- 10gE hardware is still pretty expensive.
- And even if something existed today, there'd be a predictably long slog to get customers to evaluate it and then implement it.
So nothing is going to happen tomorrow, or the next day.
But I bet that there are lots of vendors taking a hard look at FCoE. I know that EMC is.
It's safe to bet that 10gE hardware will come down in price, as did 1Gb before that, and 100baseT did before that. I'm still waiting for the first motherboard that has 10gE onboard, rather than add-on.
Such is the way of things.
And if the price gets low enough, and the performance is there, and the vendor ecosystem is there, and if it's simply an extended variation of what people already know today (FC) in terms of behavior and management -- well, I would offer that it has a helluva better chance of showing significant enterprise adoption as compared to its predecessor, iSCSI.
At least, from where I sit.
Now, before I get flamed by the iSCSI Fanboy Club (again!), let's balance out the discussion a bit.
iSCSI does very well in certain market segments. That's not going to change. Especially where your storage needs are not advanced enough to warrant a separate FC infrastructure and all that it entails.
And there are lots and lots of people who fall into that category. So, if you're a vendor, and your business model is based on iSCSI, there's still lots of people to sell to.
And there's no reason whatsoever that I can see why both protocols (iSCSI and FCoE) couldn't live on the same physical Ethernet infrastructure, which means that some people might look at FCoE as something they might consider if for some reason iSCSI doesn't meet their needs.
So, I'm not seeing this as a winner-takes-all competitive battle between two protocols, although I'm sure I'm going to read at least one article along those line. And there be some who feel threatened by this new standard.
Ultimately, in the FC vs. Ethernet discussion, many of suspect what the end of the movie should look like.
Is this the way forward?