Rackable Systems' C1000

This DC-powered application server takes the heat out of data center operations with its high density and low power consumptions.

May 2, 2006

6 Min Read
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Rackable Systems has a goal: Create servers that use less power and produce less heat, thereby reducing the electricity costs for powering its rackmount systems and cooling the data center. Toward that end, the company has rolled out the 1U C1000, the latest in its line of DC-powered servers. But though C1000 users may gain savings in electrical efficiency, the product's use of Intel's dual-core 2.0-GHz Sossaman chips leaves something to be desired. The Sossaman is a chopped-down 32-bit chip that lacks support for EM64T (Extended Memory 64 Technology), Hyperthreading, SpeedStep and Virtualization Technology in a world where more and more applications are using these features. That might be too high a price for some companies to pay for saving some watts.

Because the C1000 is a half-depth system, you can squeeze twice as many C1000s in a standard cabinet as you can full-depth 1U Dell PowerEdge 1850s or Hewlett-Packard Proliant DLs, the two AC-powered, dual-core capable systems Rackable considers its chief competitors. That doubles the processor power (in terms of square-foot ratio) in a server environment when compared to other 1U systems. The CPU muscle-to-space advantages may be less obvious compared with, say, a similarly sized ProLiant blade server enclosure, which can support up to 16 blades, each using up to two CPUs, and up to six enclosures per 42U rack.Power Savings

By distributing redundant DC power to each server--and replacing the standard AC power supply with a more efficient DC power supply--approximately 20 percent to 40 percent of the thermal load is shifted outside the server to 3200 watt AC-to-DC rectifiers at the top of each rack, where heat can be vented into the HVAC system, reducing monthly power costs by up to 30 percent, according to the vendor. Total cost of ownership stands to improve from the energy savings stemming from more efficient conversion of AC to DC power. Based on Rackable Systems' projected -48VDC at165W per-unit power consumption, the cost of power consumption of a full 88-unit rack of Rackable Systems' C1000 servers over four years is $44,195.98, versus a similarly configured Dell PowerEdge 1850, which clocks in at $96,427.58. That's roughly a 65 percent savings for the C1000 in power consumption.

However, note that 88 PowerEdge servers at a (nominal) per-unit cost of $1,800 costs a total of $158,400, versus Rackable's C1000 offering at a total of $353,760. Obviously the amortized power savings per-unit (over four years) must be weighed against the 2.18 times cost increase versus similar Dell systems.

A future version will support Intel's upcoming 32-bit "Woodcrest" chip, which promises even greater advances in reducing power consumption. The company also plans 64-bit versions of the server.

Test SetupMy test environment was AC only, so Rackable Systems provided its AC-to-DC rectifier, which required no major infrastructure changes. Typically a DC power rail would be in place to feed each racked server within a DC cabinet. So servers that require AC power can use extant AC power, and the DC-powered units can be placed along with them without major overhauls in the data center's power distribution.

Technically the system is solid--4 GB of RAM and an 80-GB 7200 RPM SATA hard drive were included on my test system. A single PCI-e slot is the only internal expansion provided. The system lacks an integrated disk array beyond the primary hard drive, which means storage for a multi-hundred-user base on a single server is probably a bad idea. However, the unit's Gigabit Ethernet connectivity makes connecting network-attached storage devices viable. Two Gigabit Ethernet ports are on the front of the unit, so take care in designing infrastructure vis-à-vis physical layout of cable routes if NAS is to be used.

Costs Pack a Punch

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Setting up the server was a snap; mounting the small form-factor unit on a rack is a single-person job. Rackable's power rail contains a "blind" power coupler so that its patented back-to-back mounting scheme requires no juggling cables behind the servers.In terms of basic CPU performance, the unit is impressively responsive. Based on what I saw during heavy load testing of the C1000 during rendering tests and CPU stress tests (using CPU-MARK 2.1, which tests dual-core performance), the C1000 seemed adequate. A server farm for rendering or for application service would benefit from the C1000's power efficiency and performance.

Not every data center is wired for DC power, nor is every data center equipped with some sort of on-site rectifier. Using Rackable's built-in DC power conversion hardware is far less expensive than rewiring an entire data center, particularly if the servers are placed in a power grid with conventional AC-based servers. Rackable's AC-to-DC conversion equipment is nominal, though, so managers that choose this direction would probably want a big system from the likes of Eaton power. These can be roof-mounted.

The tested configuration's list price of $4,020 is roughly twice the cost of a comparably equipped AC system. I'd like to conclude that the power-cost savings you should see would make this system well worth the investment, but the Sossaman chip's long-term viability is a concern. The same system with a more capable dual-core chip, which should be on the way from Rackable, sounds more promising.

Bill Silvey is an IT professional specializing in desktop-to-server workstation connectivity and enterprise solutions. Write to him at [email protected].

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