Data Centre

The CERN Data Centre is the heart of CERN’s entire scientific, administrative, and computing infrastructure. All services, including email, scientific data management and videoconferencing use equipment based in the data centre. The 95 000 processor cores and 10 000 servers hosted in its three rooms run 24/7. A remote extension of the CERN Data Centre is hosted at the Wigner Research Centre for Physics in Hungary, and it provides the extra computing power required to cover CERN’s needs.


State-of-the-art network equipment and over 35 000 km of optical fibre provide the infrastructure that is essential for running the computing facilities and services of the laboratory as well as for transferring the colossal amount of LHC data to and from the data centre. Some 4 000 users can simultaneously use the WiFi network, while 6 000 devices are connected to it every day. The CERN data centre processes one petabyte of data each day, or the equivalent of around 210 000 DVDs. In 2013 the Wigner data centre in Hungary was added to increase the overall capacity, with two 100 Gigabit per second circuits linking the two sites.


The electrical infrastructure is a vital element of the data centre. Strategies for increasing power efficiency are permanently investigated to be able to maximise the computing power serving the CERN’s infrastructure and scientific programme whilst staying within the 3.5 megawatt electrical capacity envelope available in the data centre. In the case of a major electrical cut, Uninterruptible Power Supplies (UPS) provide time for all the non-critical systems to be properly shutdown and a combination of UPS systems and diesel generators ensure that the critical services keep working.

Data Storage

The LHC experiments produce over 30 petabytes of data per year. These are transferred to the data centre where initial data reconstruction and archival is performed. Over 100 petabytes are kept in mass-storage systems - the equivalent of 700 years of full HD-quality movies. Magnetic tapes are used as the main long-term storage medium. To access the files, special robotic arms find the right tapes and load them into the tape drives. More than 480 million experiment files are stored in the data centre.


Efficient cooling is a key element of the data centre. When the outside temperature is low, air can be used to cool the servers, otherwise chiller systems are used to cool the data centre air. Cold air is distributed via the blue ducts on the sides of the data centre room. It then goes under the false floor and into the closed server aisles through the perforated floor tiles, to be drawn finally through the servers to cool them. Some servers are water-cooled using active or passive heat exchangers in their rear doors, providing a higher cooling capacity per rack.

Google Virtual Tour

Use Streetview to walk around inside the Data Centre.

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Wigner Data Centre

See the presentation about the Wigner Data Centre

In order to be able to meet the ever-increasing demands of the LHC experiments, and to be able to ensure the availability of critical services in the event of a major incident at the CERN Data Centre, the new Wigner Data Centre in Budapest was inaugurated in June 2013 by the Hungarian Prime Minister in the presence of the CERN Director General and the President of the Hungarian Academy of Science as seen in the photo to the right.

To date, a capacity of around 10% of the capacity of the CERN Data Centre has installed at the Wigner Data Centre. This will be gradually increased over the course of the potential 7-year contract to a level comparable with that of the CERN Data Centre.

The Wigner Data Centre can be considered as a logical extension of the CERN Data Centre with the equipment being managed and operated from CERN in the same way as the equipment in the CERN Data Centre. Only activities requiring physical access to the equipment are being performed by the Wigner Data Centre staff, e.g. installation of equipment into racks, repairs to the servers, etc.

The CERN and Wigner Data Centres are connected via two independent and dedicated 100Gbps circuits, with a bandwidth equivalent to the transfer of 5 full DVDs per second.



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