Microsoft plans to build a new data centre in Dublin to help run its cloud services at a cost of around $130 million (£85 million), the company said yesterday.

The expansion is a direct result of increased demand for cloud services such as Office 365, Windows Live, Xbox Live, Bing and Windows Azure in Europe, according to Microsoft.

Microsoft's new data centre will be next-door to its existing one in the Irish capital. Construction of the data centre has begun, said a company spokeswoman, but she declined to say when it will enter service.

The new data centre will be about a third the size of the old one, at approximately 10,400 square metres, and will have up to 13MW of total power available, compared to 16MW for its 28,100 square-metre neighbour.

Increased power density

That means the new data centre will be able to accommodate servers with a power density of up to 1.3kW per square metre.

The increased power density will allow Microsoft to increase the number of servers per rack in the new data centre, as long as it can cool them down enough to keep them running.

However, Microsoft is convinced that its cooling model is up to the task, according to Stephen McGibbon, chief technology officer at Microsoft in Europe, the Middle East and Africa.

Just like its older neighbour, the new data centre will make extensive use of outside air to cool the facility year round, resulting in greater power efficiency, according to Microsoft. If free air cooling isn't enough, water can also be used to cool down incoming air. If the weather gets too cold, warm air can be recirculated to heat the facility.

Cloud reliability

The existing data centre has a power utilisation effectiveness (PUE), a measure of data centre efficiency, of 1.25, Microsoft said when it opened in 2009. That's close to the PUE of 1.07 of state-of-the-art facilities such as Facebook's in Prineville, Oregon, and better than Microsoft's 2009 average of 1.6. Microsoft didn't provide a target PUE figure for the new data centre.

Last year a power outage in Dublin affected online services from Microsoft and Amazon, which also has a data centre there, putting cloud reliability under the microscope. European customers of Microsoft's Business Productivity Online Standard Suite, the predecessor to Office 365, were affected by the power outage. Microsoft managed to get them back online after about four hours.

The new data centre has its own power infrastructure, and can be self-sufficient for a considerable time, according to McGibbon. He said that if there is an electricity failure, Microsoft has deals with diesel suppliers to keep the services up and running.