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Issue Date: April 2007

Dell, IBM push power-saving servers

18 April 2007
Timothy Prickett Morgan

Server makers Dell and IBM are looking to use the power efficiency of their respective PowerEdge and System x X64-based server lines as a means of stealing business from each other and their competitors. Dell has even gone so far as to carve out a specific energy efficient server line, dubbed Energy Smart, from its general purpose machines. IBM seems content to offer power saving options on its System x machines as well as building features for controlling power use into every machine.
Dell launched the Energy Smart variants of its ninth generation of PowerEdge servers back in December 2006. These machines used the low-voltage variants of Intel's dual-core 'Woodcrest' processors. Specifically, Dell used the Xeon 5148, which has a thermal design point (TDP) of 40 W and which runs at 2,33 GHz compared to the 3 GHz speed of the top-end Xeon 5160 part. Intel delivered the quad-core 'Clovertown' Xeon 5300 chip in November 2006, and earlier this year, Dell was able to slap it into the PowerEdge line. A low-voltage variant of Clovertown with a 50 W TDP is available in the Energy Smart line.
The Energy Smart servers use only 2,5-inch SAS drives, which use less electricity and generate less heat than a 3,5-inch SCSI or SATA drive. Dell also procures much more efficient power supplies from its partners than it uses in standard PowerEdge servers, and in fact, just how efficient they are is a trade secret. There are Energy Smart variants of the PowerEdge 1950 (1U form factor) and PowerEdge 2950 (2U form factor) rack-mounted servers, which have two processor sockets.
Dell will not say how much better those power supplies are. All that Ryan Franks, product manager for the PowerEdge server line, would say is that a typical server power supply is about 80% efficient (meaning 20% of the energy that comes into the power supply is lost as heat), and that the units used in the Energy Smart designs are 'significantly better than 80%'.
Anyway, when you add all of the energy savings up, an Energy Smart variant of the PowerEdge line offers approximately 25% better performance per watt than a regular PowerEdge server for an incremental cost of a few hundred dollars. Such power and cooling savings can easily pay for themselves in metro areas within a year, and will also allow data centres that are running out of power and airconditioning capacity to add 25% more computing infrastructure and stay within the same power and cooling envelope. "Our customers are saving around $300 per year per Energy Smart server," says Franks. And Dell can certainly justify charging that premium if customers will see that they can get the cash back over the long haul.
What Dell did not do back in December was offer a PowerEdge server with Energy Smart features that was based on Advanced Micro Devices' Opteron processors. But now, Dell has an Opteron variant of the Energy Smart design, and one that has a new feature called Dual Dynamic Power Management - which is only available on Opteron-based machines. This feature sits between the power supply and the CPU and related chipsets and regulates the amount of power going to the chips based on their performance needs. Delivering only the power that a CPU core requires - rather than just running all cores at full tilt boogie - will be particularly important as multicore processors are added to the system. On most machines, some cores will be busy and others less so. The amount of electricity delivered to a core should scale down if it is not busy, and the Opteron has features that allow this.
The PowerEdge 2970 and the Energy Smart variant of this machine is a 2U rack-mounted server with two CPU sockets. The standard machine uses regular Opteron 2200 series processors, while the Energy Smart variant uses the low-voltage Opteron HE parts. The box supports up to 32 GB of DDR2 main memory. This server only uses SAS and small form factor SATA-II drives. With two 1,8 GHz Opteron 2210 processors, 4 GB of memory, three 36 GB SAS drives, and no operating system, the PowerEdge 2970 costs $3483. (The press release says it has a base list price of $1849, but this cannot be for a usable configuration). The Energy Smart version will be available in a few weeks. No word on how much of a premium Dell will charge, but probably a few hundred bucks.
IBM has also announced that it is embracing low-voltage processors in its System x rack servers and BladeCenter blade servers, and is also adding a flash drive boot option for the BladeCenter machines that means customers do not even have to put a disk drive on a blade.
IBM is, of course, stressing that its System x and BladeCenter servers now have energy-efficient power supplies, and unlike Dell, it is being specific. IBM says that it can deliver power supplies in the System x line that have about 85% efficiency and has pushed it further in the blade servers with power supplies that run at over 90% efficiency. IBM's systems also include a feature called calibrated vector cooling, which uses a combination of fans, air flow baffles, and sensors to use the least energy possible to cool a box. IBM is also embracing the low-voltage Xeon 5100 and 5300 parts as well as the Opteron HE parts as standard options on its System x and BladeCenter machines.
The flash drive feature is thus far only available on the HS21 blade, which is a two-socket blade that supports Intel's Woodcrest and Clovertown chips. The flash drive has 4 GB of capacity, which is plenty enough to load a trimmed down operating system image and a skinny application stack. While there are boot-over-SAN options for rack and blade servers, Ishan Sehgal, worldwide BladeCenter product director at IBM, says that there have been some issues with this approach. For now, the flash drive only supports a Linux boot, and it is unclear if it will ever support Windows. The point is the flash drive uses only about 5% of the juice as a on-blade disk does.
When you add the savings up across all of the components—low voltage chips, intelligent cooling, flash drive, and so forth — a thousand servers equipped with these devices can save up to 60 W per blade and prevent the release of 10 tons of carbon dioxide into the atmosphere. (Those estimates assume a 12-hour operational day, 330 days a year.) That is enough kerosene to fly a jet between New York and London on seven round trips.
"This adds up not just in terms of dollars and cents, but also in terms of the environment and sense," says Sehgal.
Source: Computergram

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