Google's worldwide data center network spans about 900,000 servers, according to an estimate based on new information the company has deigned to share about its power use.
Previous estimates put Google's server count at over one million.
In a new report from Stanford professor Jonathan Koomey on data center energy usage, Google estimates that it accounts for less than one per cent of the energy consumed across the world's data centers, and Koomey uses this figure to extrapolate Google's worldwide server count. The web giant does not divulge the number of servers used in its network of roughly 40 data centers, which stretches from California to Finland to Asia.
According to Koomey, Google's servers account for about 2.8 per cent of the volume servers installed in data centers across the globe.
As reported by Data Center Knowledge, the Stanford prof puts the world's 2010 data center energy usage at 198.8 billion kWh, which would mean Google's facilities consume about 220 megawatts of power. "While Google is a high profile user of computer servers, less than 1% of electricity used by data centers worldwide was attributable to that company’s data center operations," Koomey writes.
"To my knowledge, this is the first time that Google has revealed specific details about their total data center electricity use (they gave me an upper bound, not an exact number, but something is better than nothing!)."
Thus, Koomey says, Google's custom built data centers are considerably more efficient than run-of-the mill corporate data centers, though he indicates that Google's infrastructure is comparable to other "cloud computing" installations. The company is now operating chillerless data centers in Belgium and Finland, with the latter facility cooled solely with water from the Baltic Sea, and it has designed its own servers with built-in batteries that remove the need for a separate UPS (uninterruptible power supply).
Speaking with The Reg, a Google software engineer who recently left the company also indicated that Google's data center technologies have moved well beyond what has been reported in the press, but he declined to provide specifics, citing a non-disclosure agreement with the company.
Though Google's servers now number about 900,000, the company has plans to expand to as many as 10 million, according to a public presentation describing a new software platform dubbed Spanner, which automatically moves and replicates loads between its data centers when traffic and hardware issues arise. According to that same Google ex-engineer, the company was just beginning to roll out Spanner when he left the company this summer. ®