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Behind the scenes of a data center –


The data center campus located in Marcoussis, about thirty kilometers south of Paris, is the largest operated by the French company Data4. Small and medium-sized companies as well as digital giants come to store their data there at a time when the cloud is developing above our heads. How does a data center work? What are the issues of data sovereignty and digital footprint in such a place? The Data4 team has opened the doors to its expansive campus at

Located just under an hour from Paris, the Marcoussis site looks like a military base. Barbed wire, barriers and identity checks greet us warmly at the entrance, while the fields and the forest extend on both sides of the campus, decorated with enormous electricity pylons. Data, considered the “new black gold”, is placed under close surveillance. This data center campus is the largest operated by the French company Data4, which has 25 data centers in France, Italy, Spain, Luxembourg and Poland. Data4 is majority owned by AXA IM (AXA Investment Managers). Fifteen data centers are housed on this 110-hectare site where nearly 300 people work. A small town, served by a small train carrying employees as well as guests. All that’s missing are the tourist comments.

However, there are many serious things that take place between the walls of the various data centers. Businesses of all kinds and sizes house their data here, usually connected via the cloud. More and more of them are using cloud providers (Microsoft, Google, Amazon for the most important ones) to manage the storage of their data in data centers.

“We have three types of customers. First the digital giants, whether French or American, who must find a place to host their data. The second is the integrators who come to host, on behalf of companies of often modest size, the computer servers of their customers. The third are large corporations. We host here half of the CAC40 customers who come to store their own servers in this secure place, to which they are the only ones to have access”, explains Olivier de Nomazy, Product and Innovation Manager at DATA4.

Behind the gates, the servers

Moving from a clean data center to the cloud allows access to information from anywhere at any time. Very concretely, computer servers (calculation and storage servers) are hosted in the data center. A software layer will make it possible to virtualize these servers and thus access this data remotely. This allows employees of a company to access data or run an application anywhere in the world. “We are not talking here about dematerialization. The data remains on computer servers. But with the cloud, they can be moved easily. Previously, companies had their computer equipment in their premises so that they could manage it. This is much less the case today”, completes Olivier de Nomazy. The cloud also gives the possibility of adapting computing resources according to connection peaks.

The 4 jobs of a data center

The main function of a data center is to house IT equipment in the best possible conditions. To do this, companies like Data4 have four main missions. The company takes us to server “colocation” rooms, the maze of corridors, the roof of a data center and the machine rooms to introduce them to us.

The first mission is to ensure data security. On the Marcoussis site, some rooms require up to 7 levels of authentication and use biometric technology.

The second mission is to provide the electricity necessary for the operation of the servers. “A computer server consumes a lot of energy. All of the computer servers running in France represent approximately 1% of French electricity consumption,” says Olivier de Nomazy. The campus receives electricity at 90,000 volts, which the company will then gradually transform through transformers until it reaches 400 volts. To compensate for any breakdowns, the campus is equipped with generators and batteries that take over in just a few seconds.

Electricity generators take over in the event of a breakdown

The third mission is to ensure the air conditioning of the computer rooms. Data4 uses two methods in particular, “free cooling” and “free chilling”. These systems allow outside air to be used to supply the water cooling system when temperatures are lower. But reducing the carbon footprint of buildings like data centers also involves building materials. “We must realize that a significant part of the environmental contribution of the digital world is linked to construction”, says the Product and Innovation Manager at DATA4. On the Marcoussis site, the buildings are regularly under construction to ensure their energy efficiency. The company is working on the introduction of predictive maintenance, based on artificial intelligence algorithms, which could facilitate the management of buildings and their cooling.

Rooftop cooling system

Finally, the fourth mission of a data center is to ensure server connectivity. Without the Internet, it is not possible to connect them to the cloud. Many telecom operators, European and American, have their dedicated spaces in the rooms.

The rise of the cloud raises the question of sovereignty

In Tourism, several companies such as Saber, Amadeus and SNCF have decided to migrate their data to the cloud, accompanied by American digital giants who dominate the market. Decisions that raise questions, particularly in terms of sovereignty. For Olivier de Nomazy, several safeguards nevertheless make it possible to protect oneself. Today, the European Data Protection Regulation (GDPR) obliges cloud providers to host the data of Europeans in Europe. The “Zero Trust” security process prevents the host or cloud provider from accessing the data. Finally, a large number of companies are now implementing hybrid architectures. On the one hand, they deploy a private cloud on their own infrastructures for sensitive data and they use the public cloud managed by cloud providers for less sensitive data.

To make it possible to store data as close as possible to companies and therefore to ensure their sovereignty, Data4 now aims to be deployed in secondary cities in Europe. Since its fundraising of 650 million euros in 2020, the company wants to double in volume by 2024.

See also: What is a data center used for and what role does it play in the rise of the cloud?

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