On 23 February 2024, a brand-new data centre was inaugurated on CERN’s Prévessin site (France), marking the completion of a major project for the Organization’s computing strategy. Spanning more than 6000 square metres and including six rooms for IT equipment with a cooling capacity of 2 MW each, the centre will host CPU (central processing unit) servers for physics data processing as well as a small amount of CPU servers and storage capacity for business continuity and disaster recovery (for example, when data is corrupted). CERN’s main data centre on the Meyrin site (Switzerland) will continue to house the majority of the Organization’s data storage capacity.
The rate of data production of the experiments at the Large Hadron Collider (LHC) continues to grow, already reaching some 45 petabytes per week, and this is expected to double in the era of the High-Luminosity LHC, the major upgrade of CERN’s current flagship accelerator, the LHC. The data from these experiments is fed into the Worldwide LHC Computing Grid (WLCG), a collaboration of around 170 data centres distributed across more than 40 countries, with a storage capacity of about 3 exabytes and one million CPU cores distributed across the network. While the Meyrin data centre has so far performed the Tier 0 role, that is, the core for the LHC Computing Grid, the Prévessin centre will provide vital additional computing capacity to CERN.
The new building was built in a record time of less than two years. It complies with strict technical requirements to ensure its environmental sustainability, and is equipped with an efficient heat-recovery system that will contribute to heating buildings on the Prévessin site.
The backbones of our interconnected world, data centres are energy-intensive infrastructures. According to a recent report, their energy consumption accounts for about 1.5% of the European Union’s total electricity consumption. Two parameters characterise the environmental sustainability of a data centre: the power usage effectiveness (PUE) – the ratio of total data centre input power to IT load power – and the water usage effectiveness (WUE) – the ratio between the use of water in data centre systems and the energy consumption of the IT equipment.
The new Prévessin centre has a PUE target of 1.1, lower than the worldwide average of 1.6, and close to 1.0, which would be the value for a perfectly efficient data centre, where all the power is delivered to the IT equipment.
It has a WUE target of 0.379 litres per kWh thanks to an innovative water recycling system. The cooling system will be automatically triggered when the outside temperature reaches 20 degrees Celsius. Five huge fan-walls installed in each room will ensure that the overall temperature does not exceed 32 degrees Celsius.
The new centre was designed, built and will be operated in the framework of a FIDIC (International Federation of Consulting Engineers) Gold Book contract, which also ensures its financial sustainability. The building’s IT rooms will gradually be equipped with up to 78 racks each. Starting from the top-floor rooms, they are expected to be fully equipped over the next ten years.