Data center building blocks

Storage networking vendors have laid out their vision of the data center of the near future. It consists of Fibre Channel (FC) and Ethernet working in perfect harmony, aided by new developments such as Data Center Ethernet and FC over Ethernet (FCoE) feeding into massive backbone switches.

It's still only a vision. Data Center Ethernet and FCoE remain on the drawing board, and recently launched converged network platforms from Brocade Communications Systems and Cisco Systems won't be complete without them. For now, all the talk of FCoE, Data Center (or Enhanced) Ethernet and converged networks could make a storage manager's head spin. Not to mention the debate around whether 8Gb FC is worth the price or if it's better to wait for 10Gb Ethernet. And if Ethernet is the way to go, should it be via iSCSI or FCoE?

"It's probably overkill now," says Ed Delgado, storage administrator at financial services firm RiskMetrics Group, of the choices next-generation data centers will bring.

Delgado is considering upgrading from Brocade fabric switches to a director because his firm's EMC SAN keeps growing. But his more immediate concern is whether to go to 4Gb or 8Gb FC instead of worrying about FCoE or converged networks.

"Most of our architecture is 2Gb," he says. "Four gig came out already, and now 8Gb is out. So, maybe let's just skip 4Gb and jump right to 8Gb."

FCoE probably won't become mainstream before 2010, but that hasn't stopped Brocade and Cisco from laying out their convergence visions.

From Brocade's perspective, the future is the DCX Backbone director. When two DCXes are trunked, you get an 896-port behemoth. The DCX supports Brocade's bread-and-butter FC (including 8Gb), as well as iSCSI, Gigabit Ethernet, Ficon and FC over IP.

Cisco counters with the Nexus platform, a larger version of its Ethernet Catalyst family. The first of these switches, the Nexus 7000, holds 512 ports for 10Gb Ethernet and 768 ports for 1Gb Ethernet, but has no FC capabilities yet.

The two major ingredients of both products are waiting on standards to be worked out. Data Center Ethernet is a spec in the works designed to avoid the dropped packets that prevent Ethernet from being used in most storage networks today. When FCoE is ready, Brocade's DCX and Cisco's Nexus switches will be able to integrate FC and Ethernet connectivity. But FCoE isn't expected to even start showing up until late 2008.

Analysts say the next-generation data center visions of Brocade and Cisco won't seem so different when FCoE arrives but, today, each centers on its traditional strength.

"Fundamentally, they're going to look similar," says Greg Schulz, senior analyst and founder at StorageIO Group, Stillwater, MN. "Cisco will have more of a network look and feel. Brocade will have more of a storage look and feel. Brocade has more Fibre Channel out there, but less Ethernet. Now they're like boxers getting ready to get into the ring. Eventually, they'll square off with their functionality. But they're not even in the ring yet."

Bob Laliberte, an analyst at Milford, MA-based Enterprise Strategy Group (ESG), agrees that DCX and Nexus are a ways from crossing paths. "A lot of people are pitting them together, and they will be head-to-head when FCoE comes out; but until then, Cisco will be favored in networking and Brocade in storage," says Laliberte.

That means DCX Backbone and Nexus will be used by different teams in the interim. "The networking team will be interested in Nexus and storage teams will be interested in DCX Backbone," says Laliberte. "If the networking side is buying Nexus and the storage side is buying DCX, the interesting thing will be how well they work together. The intersection point is when FCoE comes out."

There will be other vendors' wares in play as well. HBA vendors Emulex and QLogic are hurrying out 8Gb devices, as well as cards that support FCoE. Cisco will get its FCoE technology from Nuova Systems--Cisco owns 80% of the firm and has an option to acquire the other 20%.

Xsigo Systems (which uses InfiniBand to virtualize I/O), as well as Ethernet switch vendors Extreme Networks, Force10 Networks, Foundry Networks, Juniper Networks and Woven Systems, hope 10Gb and Data Center Ethernet will make their products look better. But in the long run, the backbone for the data center will likely come down to spine provided by Brocade and Cisco.

That backbone will be costly. IBM sells the Brocade DCX Backbone for an entry-level price of $390,000. A Nexus 7000 is expected to cost approximately $200,000 for a typical data center configuration--and that's without FC switches and directors.

--Dave Raffo

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