Microsoft has a million servers: So what’s it doing with them?

At Microsoft’s 2013 Worldwide Partner Conference, CEO Steve Ballmer gave us a very interesting titbit about the scale of Microsoft’s server operations. “We have something over a million servers in our datacentre infrastructure,” he said. Furthermore, Ballmer even went on to say that “Google is bigger” and “Amazon is a little bit smaller.” It is extremely rare to hear such direct figures; in almost two decades, Google and Amazon have never even put a rough figure on their server count – and now Ballmer has been on stage, giving up their secrets.

Prior to Ballmer’s keynote speech, the best guesstimate had put Google’s server count at around 900,000 in 2010; so, hearing confirmation that it’s now over one million isn’t a big surprise. We’ve never had any data from Amazon, other than abstract figures, such as the number of objects stored in its cloud. Given the scale of Amazon Web Services (AWS), though, which is by far and away the largest public cloud, close to one million servers is a reasonable figure.

What Microsoft is doing with one million servers, though, is anyone’s guess. Azure is nowhere near the size of AWS, and Bing and Outlook.com are much smaller than Google Search and Gmail. Microsoft has hosted applications such as Office 365 and the servers that power Xbox Live, but still, a million is a stretch.

Just so you have some idea of the scale of one million servers, a large data centre might be the home of 50,000 to 100,000 servers – so, we’re looking at around 10 to 20 facilities that are Microsoft-owned, or perhaps owned and operated by other companies, with floor space rented by Microsoft.

At roughly 200 watts per server, plus perhaps another 50 watts of overhead (cooling, distribution losses, routers), that’s a total power consumption of 250 megawatts – or around two terawatt-hours (TWh) per year. That’s about the same amount of power used by 177,000 average American homes (at 11,280 kWh per year).

Assuming each server costs on average $1,000 (£650) – some will be beefy, some will be wimpy – that’s $1 billion (£650 million) of capital expenditure; and that’s before you build the data centres. Data centres (Microsoft's centre in San Antonio is pictured below) are usually priced by the megawatt, with modern data centres coming in at around $10 million (£6.5 million) per megawatt. 250 megawatts, then, equates to $2.5 billion (£1.65 billion). $3.5 billion (£2.3 billion) isn’t an unfathomable amount for Microsoft, which has around $70 billion (£46 billion) in the bank – but it’s not pocket change. This is before the amount of money spent on power and staffing, of course, which would cost another few hundred million per year.

These figures, as large as they may seem, are actually quite reasonable and in-line with the very rapid rollout that we’ve seen over the last few years. Computing is definitely moving to the cloud, and Microsoft, Google, and Amazon are all in it to win it. They are all building multiple, brand new, dedicated data centres as you read this – usually in places where electricity is cheap, or cooling is free, to keep costs down, and often using their own custom hardware and topologies to ensure high efficiency.

Finally, though, we come back to the most pertinent question: What is Microsoft doing with one million servers? Microsoft said that the Xbox One will be backed by 300,000 servers – a truly astronomical figure – but its other web services just don’t add up. Bing, Outlook.com (Hotmail), Azure, and a handful of other smaller services really shouldn’t account for 700,000 servers. The only answer that really makes sense is that most of the servers are for future capacity – or, in other words, build it and they will come. Here’s hoping.