Energy has become a central design point in the datacenter. It is such a critical factor when looking at the cost of running your hosted applications. The U.S. Environmental Protection Agency (EPA) recently released the Energy Star logo for servers. This is a great first step in managing efficiency but it will be interesting when “version 2” hit’s the street. The next rating will look at compute performance and energy efficiency and will be out later part of this year. Given the Green IT movement, I am pleased to see the star rating. I am, however, a bit disappointed in the lack of focus around the number of cores.
The EPA has noted in the cover memo of the Final Draft: “EPA continues to believe that the best indicator of the base Idle level for Computer Systems is the number of discrete processors, not the total number of cores.”
The standard requirements for the first release are as follows:
- Power Supplies Efficiency. The power supply for the server must meet specific minimum efficiency requirements across a range of loads (approximately an 85% efficiency and above for higher loads). Also, a minimum power factor is required for the same range of loads (approximately a 0.80 factor and above for higher loads). A lower power factor draws more current for the same amount of power transferred, resulting in less performance per watt.
- Active Power. There is a maximum allowance for the idle power consumption of 1 and 2 socket servers. Systems that are 4 socket and above must enable processor level power management to reduce power utilization during idle and low utilization states.
- Standard Information. Server vendors are required to provide a standardized data sheet for each Energy Star qualified server. The data must be posted on the vendor’s website.
- Data Measurement and Output. The server must have the ability to provide data on the input power in terms of watts, inlet air temperature, and utilization of the CPU. This can be done through the use of a service processor, embedded power and thermal meters, or a preinstalled OS. The collected data needs to be able to be integrated into a third-party system or datacenter management solution.
I know this is a first step but I fear that the energy efficiency rating could add some confusion.
Vendors innovate for multi-core because of multiple reasons: it not only saves cost and makes the systems cheaper, but it also saves energy, as integrating a greater number of processing cores on a single socket burns less overall system-level energy than distributing those cores over multiple sockets.
As such, the energy efficiency (performance per watt) of 8-core systems is greater than that of dual or quad-core systems, because fewer are needed to service a given quantum of workload. Yet, because the EPA grants idle power allowances only on the basis of socket count, not core count, 8-core systems, which are more energy efficient, are penalized, since their lower socket count restricts them to a lower idle power allowance.
The unfortunate effect of the EPA’s present stance on not recognizing this innovation of multi-core microprocessors, and the energy savings benefits thereof, will have a counterproductive effect on customers seeking to save energy in their data center through the deployment of Energy Star compliant servers. By penalizing rather than rewarding the innovation of reducing data center level power through the use of fewer servers with more processing cores per server, the EPA will create the conditions for the unintended consequence of increasing total power consumption at the data center level through the Energy Star for Servers program.
I hope that the EPA is looking into this with the next release.