The 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 90 000 processor cores and 10 000 servers hosted in its three rooms run 24/7. A remote extension of the CERN data centre has recently been inaugurated. Hosted at the Wigner Research Centre for Physics in Hungary, 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.
The LHC experiments produce over 25 petabytes of data per year. These are transferred to the data centre where initial data reconstruction and archival is performed. 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.