In 1919 Irish poet WB Yeats wrote ‘The Second Coming’, a work that conjured the image of a “spiritus mudi”—a vast warehouse that contained all the archetypes of human concepts. This enormous storage facility was located somewhere out in the inhospitable desert, yet magically accessible to every person walking the earth. Almost a century later, in the age of high speed data transport, intelligent networks and virtualisation, it’s easy to forget that behind the almost magical connection delivering information to the screen in front of the end user’s eyes, there is a solid, squat building full of humming electrical equipment. The datacentre is almost an abstract concept in itself. It sits at the heart of the network and carries out many of the critical tasks that keep the services fl owing; rarely, if ever, occupying the attention of the millions of customers it serves.

The vision of a datacentre as a hulking steel warehouse packed with racks and racks of servers studded with flashing lights isn’t far wrong. But what actually goes on behind the glowing LEDs? A telecom operator’s datacentre houses critical applications such as OSS and BSS and everything essential for running the Master Control Centre. As a result, a datacentre requires 24/7 uninterrupted availability, high security, high speed connectivity and lots and lots of power. That power is by far the biggest factor in running a datacentre, so if a carrier can reduce the electricity bill by 30 per cent, they can dramatically reduce cost. This consideration has influenced a number of approaches to datacentre building. Scale—a common concern in the telecoms industry—is another important dynamic affecting which approach an operator takes.