From these tests, it was determined that they could add another server per rack by reducing platform power consumption to as low as 250W, all the while maintaining an acceptable performance level.
The next test was at the rack level using Datacenter Manager. Rather than capping the power level of individual servers, they developed a power-capping policy of 750W for a three-server rack (250W per server). Without power capping, the rack level of power consumption hit 900W. With the power capping in place, power consumption was clumped down close to 750W. There was some fluctuation due to the dynamic nature of the Baidu app's workload, but overall, performance remained at an acceptable level, despite the cap on power.
In total, Intel and Baidu managed to reduce power consumption by as much as 50W at the server level, without significant impact on workload performance. At the rack level, they saw a potential for around 20 percent more capacity within the same power envelope and without performance impacts.
Intel isn't the only vendor out there offering power-capping technology. AMD, IBM, Dell, and HP have added power-capping features to their server-management software. I can see datacenter operators embracing this sort of technology with caution, as no one wants to be responsible for crippling business-critical applications. (The same could be said for the practice of powering down servers when they aren't in use.) At the same time, as datacenters continue to face limits on space and power, and as power-capping technology matures and proves its value in real-world applications, more companies should be amenable to at least giving it a test run.
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