Fibre Channel vs. Ethernet: Is the storage networking war over?

In virtualized data centers, Ethernet is rapidly replacing Fibre Channel as the preferred shared storage transport mechanism. Here’s why.

Increasingly, IT architects selecting new virtualized data center infrastructure are deciding whether to use Fibre Channel or Ethernet for shared-storage connectivity. Even if you have a Fibre Channel infrastructure, there are compelling reasons to choose Ethernet for future investments.

Indeed, Fibre Channel won’t go quietly. Many organizations won’t replace their large Fibre Channel investments any time soon.  But Ethernet’s ever-increasing bandwidth and ability to run multiple storage and networking protocols gives it the edge, today.

If you’re still on the fence, consider the following four reasons why continuing with Fibre Channel may not be wise.

1. Generational speed improvements
Raw mathematics is one reason for Ethernet’s ascendency over Fibre Channel. Fibre Channel’s generational speed improvements generally occur in powers of two. For example, 2 Gb Fibre Channel connections became 4 Gb, and then 8 Gb.

Those improvements, in addition to the lossless nature of Fibre Channel (fiber optic cabling ensures that data isn’t corrupted), provided excellent performance in storage networking’s early years.

But Ethernet’s generational throughput improvements far outpace Fibre Channel’s. For instance, Ethernet’s paltry 100 Mb connections quickly became 1 Gb. And now 10 Gb equipment is available, with 40 Gb and 100 Gb rates on the horizon.

2. The simplicity of TCP/IP
Properly configuring Fibre Channel requires an arcane body of knowledge, because Fibre Channel vendors never agreed on core standards. As a result, each vendor offering has different configuration and administration nuances, which is a recipe for unfathomable complexity.

If you’re an IT professional with an advanced degree in storage, you have a reason to keep Fibre Channel. But for the rest of us, there’s Ethernet’s well-known TCP/IP protocol.

Also helping Ethernet’s cause is that Fibre Channel can run atop an Ethernet network, in the form of Fibre Channel over Ethernet (FCoE). And the high-level FCoE and iSCSI (the storage protocol for Ethernet) design decisions are similar. For example, many of the architectures, security measures and designs that make sense for Ethernet networks will translate to FCoE.

3. Ethernet cabling is more flexible and durable
What’s your favorite string of swear words when you accidentally snap a strand of Fibre Channel cabling? 

Is that string as long as the strand’s run under the datacenter floor, or short as your temper when you realize you’ll be pulling yet another replacement very, very carefully?

Consolidating storage on to Ethernet will transfer your storage traffic to Ethernet’s user-friendly copper, which lays nicely under your datacenter floor or in trays over data center racks. It also coils much better for storage. 

In short, using Ethernet for both storage and networking eliminates the need for Fibre Channel cabling and optimizes your overall cable cost outlay.

4. Ethernet requires less ports
Not long ago, best practices suggested that virtual hosts have a minimum of six network interface cards (NICs) for Ethernet-based storage. (But dropping eight NICs into a server wasn’t unheard of.) The large number of NICs was necessary to segregate traffic and maintain capacity in the days of 1 Gb NICs.

Today, the six-NIC minimum has grown quaint to the point of being humorous. Now virtualization servers typically use a pair of really fast 10 Gb NICs to handle all virtualization I/O, including storage, production networking, management and migration traffic. Fewer cables and ports mean less effort and chance for mistakes, lower costs as well as a much cleaner data center.

Fibre Channel is deeply entrenched in today’s data centers, and has many redeeming qualities. But the writing is on the wall: network convergence is upon us. Ethernet will soon reign supreme and replace Fibre Channel for shared storage connectivity.

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