Data Center

A data center is a building housing a great many computers that work non-stop. These computers have no keyboard and no screen. They are used over the internet, by people and programs in entirely different locations. Such computers are called servers, because they serve other devices: they deliver videos, store photos, or compute answers. To ensure they never fail, a data center has its own power supply, its own cooling, and multiple internet connections. Sizes range from a single room in a company to halls covering the area of several football fields.

The foundation of the digital economy

Almost everything that happens on a phone actually happens somewhere else. A search query isn’t answered on the device, but in a data center. The same goes for Netflix, online banking, school clouds, and games with an online mode. If a large data center fails, millions of people are affected instantly. In 2021, an outage at a single provider knocked out large parts of well-known websites for hours.

For companies, this is also a matter of money. Building your own data center costs hundreds of millions of euros. That’s why most companies simply rent computing power from providers like Amazon, Microsoft, or Google. This rental model is called the cloud. The three companies mentioned now earn more from it than from many of their better-known products.

Since the AI boom, data centers have also become a political topic. They need enormous amounts of electricity, often as much as a small town. Worldwide estimates put them at around two percent of total electricity consumption, with an upward trend. Where new facilities are built therefore often depends on whether enough power and cooling water are available.

From server rack to cooling system

The servers sit in narrow metal cabinets called racks. A rack is roughly as tall as a wardrobe and holds dozens of flat computers. Many racks stand in long rows, with aisles left between them for technicians. The devices are connected by network cables, usually fiber optic, which transmit data as light signals.

The biggest technical problem is heat. Every running chip ultimately releases its energy as heat. Without cooling, a fully occupied room would become unbearably hot within minutes. That’s why cooled air is blown through the racks, and in modern AI facilities, increasingly water is piped directly to the chips as well. Part of the electricity, then, doesn’t go into computing but into cooling.

On top of that comes protection against failures. There are batteries for the first seconds of a power outage and diesel generators for longer interruptions. Important data is stored multiple times on different hard drives, often even in different buildings. A common misconception is that the cloud is something bodiless. It is exactly the opposite: concrete, cables, fans, and diesel tanks.

Where you’ll encounter the term in the news

In business news, data centers almost always appear in connection with AI. Companies announce billions in investments in new facilities to train and run AI models. What’s needed for this are, above all, graphics chips — specialized processors that carry out many calculations simultaneously. That is the main reason the manufacturer Nvidia became one of the most valuable companies in the world.

A second topic is location. In Germany, the largest cluster is located in Frankfurt am Main, because a central internet hub is based there. In Ireland and parts of the Netherlands, new construction was temporarily halted because the power grid was reaching its limits. Data protection also plays a role: authorities and schools often require that data be kept in data centers within the EU.

In everyday life, you notice little of all this, but you feel it indirectly. Long loading times in a game can be due to the relevant server being far away. And the fact that cloud storage costs money has a simple reason: somewhere, a real hard drive is spinning for your files, in a room that has to be cooled.