The previous generation of servers -- those from just a couple of years ago -- were arguably groomed to meet businesses' seemingly insatiable demand to have as much processing power crammed into as small a space as possible. Many organizations neglected to consider the associated costs to power and cool their legions of high-powered machines. Similarly, they overlooked the prospect that their local utility would not be able to provide all the electricity necessary to keep those jam-packed datacenters humming.
Times have changed. Energy prices have shot up. Electricity supply hasn't kept up with datacenter demand. Meanwhile, companies have become increasingly concerned over the state of the environment. These shifts have spawned a new generation of servers: machines that deliver more performance per watt and, perhaps to a lesser degree, are built in a more environmentally responsible manner. Hardware makers are stepping up to meet the challenge, competing to crank out machines that satisfy both the need for speed and a keenness for greenness.
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One such company is HP, which released this week a new line of ProLiant G6 servers that, claims the company, deliver twice the performance of the previous generation of ProLiant servers -- while using half the energy. According to Doug Oathout, vice president of green IT for enterprise servers and storage, "By simply replacing servers purchased prior to 2006 with new HP ProLiant G6 servers, customers can slash their energy bills in half."
Twice as double
It's a pretty extraordinary promise, if HP can indeed deliver on it. The company is effectively saying you can double your bang (twice the performance) for half of your buck (50 percent lower energy costs). And HP is certainly not the only vendor touting the green credentials of its server hardware.
Just how are companies such as HP managing the feat of providing more powerful servers that consume less electricity? The right processor, of course, plays a key role in overall server efficiency, and AMD and Intel are working furiously to make CPUs that are high on performance and low on energy consumption.
[ How do low-power processors from AMD and Intel compare in terms of performance per watt? ]
But there are other tacks to honing a machine's overall efficiency. One approach is superior internal cooling technology. Companies, on average, spend as much on cooling servers as they do powering them.
The new HP ProLiant machines, for example, come equipped with a new feature that the company dubs "sea of sensors": 32 smart sensors that automatically monitor the heat created by the server and adjust fans accordingly. Employing sensors to adjust cooling at the datacenter level isn't new; bringing it to the server level, however, is, and it reflects just how significant a pain point cooling costs can be.
Dell too has been developing innovative approaches to cutting server cooling costs. Last year the company unveiled an innovative internal cooling design for its Power-Edge M-series blades. The system is designed to adapt to the needs of both high-end and low-end configurations. The chassis have three distinct cooling zones, each cooled by its own fan bank. In lower-end configurations where the chassis isn't fully loaded with blades, the fans on the side can run slower -- and, thus, consume less energy -- because they don't have to work as hard to cool their zone. In addition to its optimized fans (with underlying algorithms), the system boasts a superior airflow design. Dell managed this by removing impedance throughout the chassis.
Supply-side economics
Power supplies are also a major factor in the overall energy efficiency of a server. Here, vendors are taking different approaches. In the case of the new ProLiant series, for example, HP is offering customers a choice of four common-slot power supplies to meet their specific application requirements. The idea is that a power supply's overall efficiency varies depending on utilization. HP says these power supplies offer up to 92 percent efficiency on nearly all workloads.
In a related vein, Dell rolled out a 90-plus percent efficient power supply last year that it had developed in-house. According to the company, this power supply achieves higher efficiency at lower utilization levels. Most power supplies achieve their maximum level of energy efficiency only when the supply is running at 90 to 100 percent utilization. Alas, such is not the norm, as datacenters are notorious for running servers at very low utilization levels. Dell said its power supply is capable of achieving 88 percent efficiency at just 20 percent utilization.
Less is more
Yet another strategy for optimizing server-hardware efficiency is to have power and cooling components perform double (or more) duty. For example, among HP's announcements this week was the unveiling of its HP ProLiant DL1000 Multi-Node series, which includes the DL4x170h G6, offering four server nodes in a single chassis. This approach allows the various server nodes to share power and cooling infrastructure, thus delivering an 80 percent reduction in thermal components and halving the number of power supplies. Not only is this an energy saver, it means fewer materials are necessary for the unit as a whole -- an environmental benefit.
SGI (formerly Rackable Systems) took a similar shared-component approach earlier this year with the release of its CloudRack C2, a unified server cabinet built for cluster computing applications. Each tray of the CloudRack C2 is effectively an ultra-dense 1U server, complete with standard components such as processor, board, and storage drives. However, none of these trays have power supplies or fans. Rather, the CloudRack cabinet takes care of cooling and power distribution for the trays. Again, fewer moving parts means lower overall energy consumption and fewer materials.
Growing with your needs
Yet another trait emerging among the current generation of green servers: modularity. For example, part of HP's ProLiant announcement covered the ProLiant ML330 G6, a modular tower server based on Intel Xeon 5500 processors and DDR3 memory. The ML330 is built such that IT admins can add processing power and memory capacity on an as-needed basis. Rather than having to continually replace servers as your needs grow -- which is wasteful, costly, and time-consuming -- companies can simply swap out components.
Again, though, HP isn't the only vendor to offer this sort of modularity. Dell's aforementioned PowerEdge M-series blade systems, for example, come with FlexIO switch technology for easily upgrading the machine's network connectivity up to 10Gig without replacing the base switch.
I've admittedly just skimmed the surface of the types of innovations that server vendors are devising to make their wares greener. Other techniques include developing smarter management software for measuring and managing power consumption (offered by HP and IBM, for example), and building boxes that support more virtual machines.
And let's not forget there are ways for customers to wring even more energy efficiency from their servers, such as exposing their servers to significantly higher temperatures; removing superfluous components from their machines, à la Google; or powering down servers when they aren't in use. Granted, such techniques aren't traditional (yet) and thus might not be attempted at more risk-averse IT departments. Fortunately, server vendors are making green features standard on their wares, which means you can still enjoy power savings the moment you plug in the machine.