Microservers: Small Footprint, Powerful Punch

by Paul Rubens

Microservers are inexpensive, power efficient and not to be confused with blade servers. Find out whether this latest data center staple is right for you.

The iPad and other tablets may have crushed the market for tiny low-powered netbook computers, but the netbook concept is returning with a vengeance. This time, however, you'll find it in the data center, in the form of the microserver.

Netbook-style servers have been in the pipeline for some time: As far back as February 2009, ServerWatch predicted their rise. In late 2009, Intel introduced a reference design for what it saw as the new category of "microserver." This design called for 16 hot-swappable microserver nodes squeezed into a 5U rack.

More recently, in January 2011, the Server System Infrastructure (SSI) Forum released a Micro Module Server Specification, Version 1.0 in collaboration with Intel, and two Taiwan-based companies, server hardware maker Quanta and system board maker TYAN. Thanks to recent announcements from high-profile companies like Facebook, which plans to introduce microservers into its data centers, and Mozilla Corporation, which uses microservers to power the download portal which directs users to download mirrors for Firefox 4, interest in the concept is increasing.

What Is a Microserver?

So what exactly is a microserver? "We define it as any server with a large number of nodes, usually with a single socket or multiple low-power processors and shared infrastructure," Kevin Huiskes, director of cloud computing initiatives at Intel, said recently. Typically, a microserver will have two or four slots for main memory, two high-speed Ethernet ports, and Sata ports to connect up to four disk drives. Unlike a blade server, it usually does not have a management processor.

When it comes to CPUs, low-powered processors such as Intel's Xeon E3 and Atom or AMD's Athlon and Phenom processors are common choices at the moment. In the future, these are likely to be low-powered multi-core chips from other vendors like Tilera. ARM-designed processors will also be used. Intel has already announced plans for new processors aimed at the microserver market: A new server processor based on the Atom architecture is in the pipeline for 2012. Four new Xeon processors with power consumption ranging from 45 watts to less than 10W are also on the roadmap.

One of the highest profile microserver products on offer today is Dell's PowerEdge C5000 line. Each microserver node, mounted in what Dell calls a "sled," has four memory slots, a dual-port Gigabit Ethernet controller, and four Sata ports. The C5125 node has a single AMD Athlon II X2, X4 or Phenom II X4 processor -- either 25W, 45W or 65W -- and supports up to 16GB of system memory, while the C5220 has a 65W Intel Xeon E3-1200 processor and supports up to 32GB of memory. The C5000 3U chassis, known as "Viking," has dual 1400W power supplies and supports 12 sleds. Unlike a conventional blade chassis, however, it has no in-chassis management or switching.

SeaMicro is another company involved in the microserver market, and the startup's microservers are similar to netbooks in that they use Intel's low power Atom processors. The company's original 10U SM10000 chassis held 64 cards, each containing 8 Atom Z530 processors and their chipsets, and a single memory slot supporting up to 2GB of memory. The chassis backplane linked each node to in-chassis Gigabit and 10Gigabit Ethernet switches, with disk drives and controllers also built in to the chassis. It has also announced a SM10000-64 card, which holds four dual-core Atom N570 processors supporting up to 4GB memory and capable of running 64-bit code compiled for Intel Xeon or Opteron processors.

While these two companies are perhaps the best known, other microserver vendors exist, such as TYAN, which makes the FM65-B5511 microserver 4U chassis supporting 18 microserver nodes based on Xeon E3 or AMD Athlon or Phenom processors, with up to 32Gb memory and two disk drives.

Why Microservers?

So what exactly is the attraction of these tiny, low-powered computing nodes? "Microservers allow companies to become more energy efficient," said Reuben Miller, a senior research analyst for enterprise servers at IDC. "There are a large number of companies that are trying to cut costs, and microservers use less power, need less cooling and take up less space. They are not designed for high-end, mission-critical workloads or running large database applications, but they are ideal for web hosting, video steaming, downloads, web 2.0 activities like social networking, or perhaps handling corporate logins. By segmenting your workload out you can make substantial savings," he said.

Andrew Feldman, CEO of SeaMicro, agrees with this view. "The SeaMicro SM10000 family of servers use one-quarter the power and take one-quarter the space to do the same computational work as the best-in-class server on the market," he said.

Microservers vs. Server Blades

The difference between microservers and server blades is very similar to the difference between a netbook and a full-fledged laptop: A netbook is compact, consumes little power and is suitable for a limited range of light duties, while a laptop is bigger and more power hungry but can generally handle anything that is thrown at it.

Translate this into the server world, and you get blade servers, which can run any application you want -- but require substantial amounts of power and cooling, and take up a considerable amount of rack space. You can pack many more microservers into the same space, and these microservers consume less power and heat. If you need servers only for light duties such as web serving -- perhaps in a server farm where customers want their own single-tenancy server -- then microservers are ideal; a full-fledged blade would be overkill.

Of course, another alternative would be to run multiple virtual machines on a single physical server. However, it's interesting to note that Facebook is considering using microservers as an alternative to running virtual machines. That's because, according to Facebook Labs' Gio Coglitore, virtualization makes it hard to scale and because it makes the physical servers supporting multiple virtual machines more important than he would like. Microservers are inexpensive to replace, and they have a limited impact when they fail, he said.

There's another reason microservers are beginning to represent a real alternative to virtualization, and that comes down to the falling cost of microservers, Tom Nolle, principal analyst at CIMI Corporation said. "The idea of virtualization is to take a server and make it into several virtual machines because the server has more capacity than is needed for one application. But as microservers get cheaper, it makes it possible to dedicate a server to a single application again instead of sharing the server. Remember that there is a cost to virtualization, both financial and in terms of performance." Using virtualization also leads to the risk of vendor lock-in.

It is still very early days for the microserver market, and it remains to be seen whether early entrants like SeaMicro and Dell will face increased competition from established server vendors like HP and IBM. Intel for one expects to see considerable growth in the market, but forecasts in aggregate estimate that microservers will end up making up less than 10 percent of the server market for the next four to five years. SeaMicro's Feldman believes the microserver market will be worth $8 billion to $10 billion by 2015.

Paul Rubens is a journalist based in Marlow on Thames, England. He has been programming, tinkering and generally sitting in front of computer screens since his first encounter with a DEC PDP-11 in 1979.

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This article was originally published on Thursday May 26th 2011
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