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RHEL developer preview moves ARM servers closer to reality

RHEL on ARM servers has developers envisioning new apps, but the hardware and software ecosystem for 64-bit ARM is still just a vision.

BOSTON -- ARM servers haven't cracked the enterprise data center code yet, but moves by open source leader Red Hat hint at an ARM-inclusive future.

The company released a development preview of its Red Hat Enterprise Linux (RHEL) Server platform for ARM processors during Red Hat Summit here last week.

RHEL Server for ARM Development Preview 7.1 for 64-bit ARM servers is available to end users through members of the Red Hat ARM Partner Early Access Program.

While the ARM offering is "far from being productized," Red Hat will work with the community to refine and evolve the OS, according to Paul Cormier, president of technologies and products at the company. Upstream, the Fedora Project is continuing regular releases of Fedora for 64-bit ARM servers, and Red Hat's goal is to release an ARM version simultaneously with each new RHEL update.

RHEL users will be familiar with the features in the platform, including all the same utilities, Java support, compiler set and tools in the standard RHEL 7.1 code base, said Jon Masters, chief ARM architect at Red Hat.

Red Hat is working with server processor and hardware designers to tie the OS to current and future ARM hardware, including the HP Moonshot micro blade server and platforms from Dell, Lenovo and Open Compute Project members such as Hyve Solutions and StackVelocity.

Red Hat and ARM, along with other companies, have participated in the Server Base System Architecture specification for hardware designs to allow one version of the OS to work on any ARM server, said Jim Totton, vice president and general manager of Red Hat's platforms business unit. ARM seeks innovation and differentiation on the architecture by hardware developers within this standard, according to the company's representative.

Red Hat has been putting the OS through its paces and wants Linux IT shops to try porting their software over to the preview version and "get that process going," said Masters.

The long ARM of adoption

Servers don't exist in a vacuum -- applications run the show. Applications designed to run on x86 or other server architectures must be re-architected -- or new applications written for ARM. With the Developer Preview, developers can get started, Totton said.

"Software isn't really the issue people make it out to be," said Jim McGregor, principal analyst at Tirias Research in Mesa, Ariz. "We've spent years abstracting the software from the hardware through virtualization and other moves."

At the Red Hat Summit, Masters demonstrated an Apache Spark application running on the developer preview across eight 64-bit HP Moonshot servers, gathering and analyzing data from Twitter to geo-locate trending hashtags.

While Red Hat couldn't provide an availability timeframe for the supported version of RHEL Server for ARM, it will be ready jointly with the hardware OEM designs for ARM, Totton said. Red Hat is a member of Linaro, a not-for-profit organization with heavy ARM involvement that develops features and tools that exploit the Linux kernel.

One Red Hat Summit attendee looked past trial phase into the practical considerations.

"What will the pricing model look like?" asked the attendee, who is considering ARM servers for remote communications. With distributed and Internet of Things based computing, low-power ARM servers are theoretically attractive, but the number of them that would deploy doesn't fit with the standard enterprise server rack provisioning model that is comfortable with RHEL licensing.

The theoretical nature of an ARM server ecosystem means pricing could go a few different ways within the Red Hat subscription-based licensing methodology, Totton said. If, for example, ARM processors perform comparably to Intel Xeon models, pricing will probably resemble that of the x86 RHEL editions. If 64-bit ARM hardware is totally different, Red Hat will re-examine licensing to match it with how the hardware covers workloads.

"We had this same question [about licensing] when we went to multi-core processors," said Titias' McGregor. With a distributed architecture, he said, "you probably aren't going to have the same level of software everywhere in the network." McGregor predicts a multilayer or systems-level licensing scheme, based on the number of nodes in the network, for example.

Totton cautions that assumptions around power consumption, cost and performance of ARM servers are just that -- assumptions.

"Whether ARM draws less power than x86 processors or not is still an open question," he said.

ARM server makers should go after other reduced instruction set computing lines, such as IBM POWER, which already has a RHEL edition, McGregor said. Enterprise-class servers for a variety of workloads have always been a tough ARM sell, he said, but specialty applications in mega data centers and communications, especially Internet of Things, hold more promise.

ARM's representative also points to storage servers, network function virtualization, scale-out big data -- as demonstrated by Masters' Spark application -- and cloud and Web tier applications as good fits for the 64-bit architecture.

If ARM adoption climbs, said Red Hat's Totton, the differences between applications that perform better on ARM, better on x86 or comparably on both will start to appear.

ARM server chips

Unlike the Intel-dominated x86 server industry, ARM server makers have a great deal of choice for their chip supplier. It's a blessing and a curse, according to Red Hat's representatives, who rely on consistency among hardware products.

Applied Micro and Cavium are "going guns blazing" into ARM for servers, McGregor said, and "everyone's waiting on Qualcomm to move in." Avago's planned acquisition of Broadcom also potentially has ramifications for ARM in the data center. Broadcom and Qualcomm are natural choices for ARM applications, McGregor said, thanks to the companies' expertise in communications.

Meanwhile, Samsung and other potential ARM server leaders fell by the wayside. AMD started talking up Seattle earlier this year and still hasn't shown a live demo, said McGregor.


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