Facebook Targets Datacenter with Server SoC 

Facebook used this week's Open Compute Project summit to introduce a system-on-a-chip targeting the emerging micro-server market.

Code-named "Yosemite," the "server-class" SoC was developed along with Intel Corp. as part of an open server chassis intended to help scale out datacenters.

Facebook also provided additional details about its homegrown "Wedge" Ethernet switch.

The impetus for the Yosemite project was the realization that the mainstream two-socket server architecture was not longer cutting it as Facebook upgrades its far-flung infrastructure. "To provide our infrastructure with capacity that scales out with the demand, we designed a modular chassis that contains high-powered system-on-a-chip processor cards, code-named 'Yosemite'," the social media giant explained this week in a blog post.

Facebook also said it was proposing the Yosemite SoC design as a contribution to the Open Compute Project, which is meeting this week in San Jose.

Facebook and Intel launched the Yosemite effort about 18 months ago with experimentation around what Facebook called mostly "lightweight" SoCs with small cores and lower power requirements. Facebook designers said they initially packed 36 SoCs into a 2U enclosure, meaning it could scale up to 540 SoCs per rack.

They concluded that the single-thread performance of this arrangement was too low, resulting in higher latency on its web platform. The trial-and-error approach led to development of higher-power processor that retained the modular SoC approach.

The result was the Yosemite architecture with each server node designed as a plug-in module, Facebook said. Each module contains a single SoC aiming for 65 watts (as compared with 30 watts for the earlier "lightweight" approach) along with multiple memory channels, at least one local solid-state drive interface and a local management controller.

A standard module interface based on the Open Compute Project's "Group Hug" micro-server interface was designed so compliant cards can interoperate. The interface extension provides more I/O through an additional PCIe connector.

The resulting Yosemite system holds four SoC cards drawing up to 400 watts, providing about 90 watts to each SoC card. Facebook said it is specifying one shared network connection to provide both data and traffic management.

The upshot is that Yosemite represents a server-class SoC with multiple memory channels to deliver high-end computing in a micro-server at 65 watts for the SoC and 90 watts for the entire server card. Facebook also claimed the standard SoC card interface is CPU agnostic.

"This system will be fully compatible with Open Rack, which can accommodate up to 192 SoC server cards in a single rack," the blog post noted.

Frank Frankovsky, chairman of the Open Compute Project and former Facebook datacenter manager, called Yosemite "an ideal component for our disaggregated rack infrastructure."

The Yosemite server card, dubbed "Mono Lake," is based on Intel's new Xeon-based SoC. It is the first manufactured using Intel's 14-nanometer process technology.

Facebook also said Open Compute Project member Mellanox is providing multi-host support for Yosemite in its next-generation mezzanine card.

Facebook unveiled its homegrown Wedge datacenter switch and software last summer. It said this week Wedge switches are now in production "across multiple datacenters."

It also announced initial release of its open switching system code-named FBOSS. The switching system "is not a full operating system," Facebook stressed. "Rather, it is a set of applications that can be run on a standard Linux OS."

Meanwhile, the Wedge "top-of-rack switch" uses a single Broadcom Trident II ASIC for high-speed forwarding. Facebook said Wedge would be available through Taiwanese networking equipment manufacturer Accton and its OEMs partners.