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Server Virtualization Can Save Costs

Part seven in a series. Greg Schulz is the founder of StorageIO and the author of The Green and Virtual Data Center.

Computers -- also known as blade centers or blade servers, desktops, laptops, mainframes, personal computers, processors, servers, and workstations -- are a key component and resource of any data center or information factory. Computers run or execute the program software that performs various application and business functions. Hardware does not function without some form of software -- microcode, firmware, operating, or application software -- and software does not function without hardware. The next truly revolutionary technology, in my opinion, will be software that does not require hardware and hardware that does not require software. Until then, it is important to understand the relationship between the need for more processing or compute capability and the subsequent energy demands and need to improve energy efficiency to reduce power and cooling costs and their environmental impact.

In the typical data center, computers are the second largest consumer of electrical power, after cooling. In addition to requiring power, cooling, and floor space, computers have an environmental health and safety footprint in the form of electronic circuit boards, battery-backed internal power supplies, and other potentially hazardous substances that need to be recycled and disposed of properly. The larger the computer, the more components it will have; smaller computers, such as laptop or desktop workstations, have fewer and smaller components, although they do have batteries and monitors or screens.

Servers consume different amounts of electrical power and generate various amounts of heat depending on their operating mode -- for example, zero power consumption when powered off but high power consumption during startup. Servers use different amounts of energy when running with active or busy workloads and less power used during low-power, sleep, or standby modes. With the need for faster processors to do more work in less time, there is a corresponding effort by manufacturers to enable processing or computer chips to do more work per watt of energy as well as reduce the overall amount of energy consumed.

In addition to boosting energy efficiency by doing more work per watt of energy consumed, computer chips also support various energy-saving modes such as the ability to slow down and use less energy when there is less work to be done. Other approaches for reducing energy consumption include adaptive power management, intelligent power management, adaptive voltage scaling, and dynamic bandwidth switching, techniques that are focused on varying the amount of energy used by varying the performance level. As a generic example, a server's processor chip might require 1.4 volts at 3.6 GHz for high performance, 1.3 volts at 3.2 GHz for medium performance, or 1.2 volts at 2.8 GHz for low performance and energy savings. Intel SpeedStep and other energy efficiency and performance enhancements technology, such as those found in the new Intel Nelham-based processor chips, reduce energy when higher performance is not needed, but boost performance to be more efficient when work needs to be done.

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