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HHOOWW CCEERRNN DDEEAALLSSWWIITTHH TTHHEE DDAATTAA TTOORRRREENNTTExperiments at CERN generate colossal amounts of data. The Data Centre stores it, and sends it around the world for analysis.

Research and education networks such as GÉANT and its European NREN (NationalResearch and Education Network) partners provide the high-capacity bandwidth requiredby CERN to transport this data all over the globe. Without them, these types of colossalscience projects—which have the potential to change our understanding of the world—could not take place.

In this article, extracted from the CERN website, CERN gives us a window into thewonderful world of high energy physics—and the vast, ambitious and collaborative Large Hadron Collider project.

©© CCEERRNN

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OONNEE PPEETTAABBYYTTEE OOFFDDAATTAA EEVVEERRYY DDAAYYThe Data Centre processes about onepetabyte of data every day - theequivalent of around 210,000 DVDs.The centre host 11,000 servers with110,000 processor cores. Some 6000changes in the database are performedevery second.

The Grid runs more than two millionjobs per day. While the LHC is running10 gigabytes of data may be transferredfrom its servers every second.

In addition, the LHC sciencecommunity makes use of GÉANT andits global partners to enable continualdata sharing at aggregate rates of 15 -20 gigabytes per second year round.

Published with kind permission of CERN.

The original articles can be found here:hhttttpp::////hhoommee..wweebb..cceerrnn..cchh//aabboouutt//ccoommppuuttiinngghhttttpp::////hhoommee..wweebb..cceerrnn..cchh//aabboouutt//uuppddaatteess//22001155//0066//llhhcc--sseeaassoonn--22--cceerrnn--ccoommppuuttiinngg--rreeaaddyy--ddaattaa--ttoorrrreenntt

The server farm in the 1450m2 main room of the DC forms Tier 0,the first point of contact betweenexperimental data from the LHC and the Grid. As well as servers and datastorage systems for Tier 0 and furtherphysics analysis, the DC housessystems critical to the daily functioningof the laboratory. The servers undergocontinual maintenance and upgrades tomake sure that they will operate in theevent of a serious incident such as anextended power cut. Critical servers areheld in their own room, powered andcooled by dedicated equipment.

By early 2013 CERN had increasedthe power capacity of the centre from2.9 MW to 3.5 MW, allowing theinstallation of more computers. In parallel, improvements in energy-efficiency implemented in 2011 have ledto an estimated energy saving of 4.5GWh per year.

CCOOPPIINNGG WWIITTHHIINNCCRREEAASSIINNGGRREEQQUUIIRREEMMEENNTTSSIn a complementary effort to cope withthe increasing requirements for LHCcomputing, the Wigner Research Centrefor Physics in Budapest, Hungary,operates as an extension to the DC. The Wigner Data Centre as a remoteTier 0, hosting CERN equipment. Thesite also ensures full business continuityfor the critical systems in case of a majorproblem on CERN's site at Meyrin inSwitzerland.

The Meyrin site currently providessome 120 petabytes of data storage ondisk, and includes the majority of the 110,000 processing cores in the CERNDC. The Wigner DC extends thiscapacity with 43,000 cores and 70petabytes of disk data.

Approximately 600 million timesper second, particles collidewithin the Large HadronCollider (LHC). Each collision

generates particles that often decay incomplex ways into even more particles.Electronic circuits record the passage ofeach particle through a detector as aseries of electronic signals, and send thedata to the CERN Data Centre (DC) fordigital reconstruction. The digitizedsummary is recorded as a "collisionevent". Physicists must sift through the30 petabytes or so of data producedannually to determine if the collisionshave thrown up any interesting physics.

AA CCOOMMMMUUNNIITTYY OOFF88000000 PPHHYYSSIICCIISSTTSSCERN does not have the computing orfinancial resources to crunch all of thedata on site, so in 2002 it turned to gridcomputing to share the burden withcomputer centres around the world.The Worldwide LHC ComputingGrid (WLCG) – a distributed computinginfrastructure arranged in tiers – gives acommunity of over 8000 physicists nearreal-time access to LHC data. The Gridbuilds on the technology of the WorldWide Web, which was invented atCERN in 1989.

In 2012, the Wigner Centrewas one of the firstbeneficiaries of GÉANT’sterabit network, utilisingmultiple 100Gbps links. At the time David Foster,Deputy Head of the CERNIT Department said, “TheGÉANT network isfundamental to our datatransfer needs, and we’redelighted that we will becontinuing this successfulrelationship.”

UUPPDDAATTEE:: CCEERRNNRREESSTTAARRTTSS MMOOSSTTPPOOWWEERRFFUULL AATTOOMMSSMMAASSHHEERRIn June this year, theexperiments at the LargeHadron Collider (LHC)started taking data atthe new energy frontier of13 teraelectonvolts (TeV) -nearly double the energyof collisions in the LHC'sfirst three-year run. Thecollisions, which occur upto 1 billion times everysecond, send showers ofparticles through thedetectors.With every second of

run-time, gigabytes of datacome pouring intothe CERN Data Centre tobe stored, sorted andshared with physicistsworldwide.