SINGAPORE, 1 SEPTEMBER 2008 -- Server virtualisation has become a buzzword among enterprises embarking on a green data centre strategy today. However, another side of green IT exists, which cannot be ignored in order to maximise the benefits of server consolidation.
Global IT infrastructure management solutions provider, Raritan, claims that its intelligent rack power distribution units (PDUs) provide real-time monitoring of power consumption. This allows IT staff to identify servers or IT devices that are underutilised or exceeding their normal high range of usage, according to Raritan.
Called Dominion PX, each PDU also monitors rack temperature and humidity.
Dominion PX collects, aggregates and monitors power consumption data, helping the enterprise to decide which server or storage areas to virtualise, said Neil Liu (picture), Raritan's global IT director.
Testing own solution
In February 2008, Raritan deployed Dominion PX in its US data centre as an internal IT project, according to Liu. We wanted to consolidate our US data centres servers to save on floor space and power consumption cost.
He noted that five per cent of the facilitys servers are currently consolidated. Our target is to raise that figure to between 20 and 35 per cent by end-2008 or early first quarter of 2009.
According to Liu, the PDUs allowed Raritan to identify servers that emitted more heat. Such servers may then be moved to the top of the rack, allowing the heat to escape more easily.
The initiative also enabled Raritan to test Dominion PX on itself before the product was commercially released into global markets in April this year. We were confident in being a beta user because any consequences would be non-significant and there was little deployment risk involved, Liu said.
Power usage effectiveness
Power usage effectiveness (PUE) measurement is important, as server utilisation changes over time, according to Raritan. A data centre can measure its PUE by dividing the facilitys total power consumption by IT-related power consumption, Liu said.
He added that a data centre with PUE value between 1.2 and 1.8 in the industry would be considered very efficient. Following Dominion PXs deployment, we have achieved a PUE of 1.4 in our US data centre.
Other key performance indicators like targeted floor space and the US data centres electrical bill as a percentage of Raritans overall electrical cost are yet to be determined, Liu said.
While PUE may be a useful indicator of power consumption efficiency, other factors must also be considered, he noted. For example, environmental temperatures across different geographic locations can affect its value.
A word of caution
Liu noted that a servers actual power consumption never matches with the consumption value indicated on its nameplate. According to Raritan, the nameplate value indicates the maximum amount of power a device can use at any given time under any kind of workload and data centre environmental condition.
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