This vendor-written tech primer has been edited by Network World to eliminate product promotion, but readers should note it will likely favor the submitter's approach.
Hundreds of thousands of KWh are being consumed by the use of memory components in servers today. By adopting more energy-efficient components in optimized server architectures, such as lower voltage DRAMs and advanced solid-state drives (SSDs), data centers can drastically reduce power consumption and associated energy costs.
The most recent U.S. Environmental Protection Agency's (2007) report on server and data center energy efficiency shows that U.S. data center power consumption will surge from 61 billion kWhr in 2006 to about 100 billion kWhr in 2011. Data center power requirements are expected to increase as much as 20 per cent per year for the next couple of years.
THE BASICS: Green IT Research Center
Subsequently, data center power costs have skyrocketed because, for every watt of power, between 2 and 2.5W is needed to cool it. IDC analysis shows that server energy expense in 2009 accounted for 75 per cent of the total hardware cost. The firm also found that the energy expense to power and cool servers has jumped by 31 per cent in the last five years.
Various studies show that memory has become one of the biggest power consumers in the server space, which adds substantially to energy costs, including cooling. In addition, virtualization is adding to the memory challenge, as it grows in popularity in helping to drive down data center cost. The move to virtualization translates into more memory per server, thereby increasing the use of DRAM and raising the total density per storage system.
To confront the power dilemma, aggressive targets have been set by regulatory agencies like the EPA and environmentally focused technology solutions providers.
Green memory and optimized servers
To handle the challenge, buyers are tapping more energy efficient servers that can save hundreds of thousand dollars per year. Realizing the need for greater energy efficiency, server manufacturers have been optimizing their architecture including the use of power-saving "green" memory alternatives.
To better understand the server power scenario, let's take a look at 48 GB servers as an example. The power breakdown in second generation DDR2 memory consumes about 26 per cent of total power consumption as compared to 20 per cent by the CPU.
While most server designers are exploiting multi-core CPUs to enhance processing per watt, many are also migrating to new generation memories to further slash system power consumption. For that, Hewlett-Packard, Dell, IBM, Fujitsu and other OEMs are working closely with memory suppliers to tap the benefits of Green memory architectures and technologies at ultra low voltages and high density to deliver a new class of servers that dramatically improves power consumption. In so doing, they are decreasing corresponding cooling costs to lower the total cost of ownership (TCO) while accelerating return on investments (ROI).
Hence, the same 48 GB server configured with third generation Green DDR3 DRAM chips will reduce the memory power consumption dramatically. Measured data shows that by replacing second generation 60 nm 1 Gb DDR2 DRAMs operating at 1.8 V with 30 nm 4 Gb DDR3 DRAM chips operating at 1.35 V, the total power consumed by DRAM memories in each server is reduced from 102 W to 14 W, reaping a whopping 86 per cent savings. This means that at the component level, the Green DDR3 can deliver technology that can consume less than 0.29W per Gigabit of memory as opposed to 2W per Gigabit.
However, to better gauge this at the system level, let us compare the power scenario for a specific 42U server rack comprising four enclosures per rack with 16 servers in a single enclosure for a total of 64 servers or blades per rack. The above mentioned configuration equates to system-level power savings of about 44 per cent -- from 390 watts to just 220 watts.
The 44 per cent saving at the server level equates to significant TCO benefits in the enterprise space: Through the use of Green DDR3, buyers can increase server resources 80 per cent without needing to increase the power budget. In a 2000W power envelope, Green DDR3 allows for placing nine servers on a single rack instead of five. The savings become even more significant when one factors operating costs. For example: In a 1,000-server farm, only 112 racks would be needed instead of 200, cutting overhead costs proportionately by more than $60,000.
Moving to a Green DDR3 provides yearly energy savings of 2.98 Megawatt hours of electrical power per year per server, which amounts to an annual dollar savings of $194,000 per 1,000 servers. That much money would allow the purchase of another 55 servers after just one year of use. Or, simply result in a power cut of 3,000 megawatt hours over the same period of time.
SSDs bring greater savings
Additionally, optimized server architectures are taking advantage of the benefits of solid state drives (SSDs). Exploiting NAND flash technologies, SSDs are aiding optimized servers to further curtail power use and cutting associated cooling costs. With digital design and no moving parts, SSDs save much more power than traditional hard disk drives (HDDs). In comparison to a conventional 15K rpm HDD, certain SSDs can use only 1.7W in active mode for a 79 per cent drop in power consumption. Power savings in the idle mode is even greater -- about 83 per cent compared to a 15K rpm HDD.
Another measure of performance is the number of inputs and outputs per second per watt or IOPS/W. In this metric, the Green SSDs outperform the traditional 15K rpm HDDs by a huge margin. Internal tests demonstrate that second generation Green SSDs IOPS/W are 200 times higher than a 15K rpm HDD. In addition, the SSDs occupy considerably less space, and depending upon the application, a single Samsung SSD can replace between four and 40 15K rpm SAS HDDs in a server array.
Few will argue that quick payback for both Green DRAM and SSDs matters a great deal, and upon close examination, even fewer will argue about the overall cost-saving impact of Green DDR3 and Green SSDs in substantially shortening most data center's ROI.
Samsung Semiconductor Inc. is a wholly owned subsidiary of Samsung Electronics Co. Ltd. As the leader in advanced memory solutions for home, mobile and office applications, Samsung Semiconductor is the largest producer of DRAM, Flash, SRAM and high-end graphics memory. Visit www.samsung.com/GreenMemory.
Read more about data center in Network World's Data Center section.
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