Experience building and operating the CMS Tier-1 computing centres

M. Albert*, J. Bakken, D. Bonacorsi, C. Brew, C. Charlot, Chih Hao Huang, D. Colling, C. Dumitrescu, D. Fagan, F. Fassi, I. Fisk, J. Flix, L. Giacchetti, G. Gomez-Ceballos, S. Gowdy, C. Grandi, O. Gutsche, K. Hahn, B. Holzman, J. JacksonP. Kreuzer, M. Kuo, D. Mason, N. Pukhaeva, G. Qin, G. Quast, P. Rossman, A. Sartirana, A. Scheurer, G. Schott, J. Shih, P. Tader, R. Thompson, A. Tiradani, A. Trunov

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


The CMS Collaboration relies on 7 globally distributed Tier-1 computing centres located at large Universitàies and national laboratories for a second custodial copy of the CMS RAW data and primary copy of the simulated data, data serving capacity to Tier-2 centres for analysis, and the bulk of the reprocessing and event selection capacity in the experiment. The Tier-1 sites have a challenging role in CMS because they are expected to ingest and archive data from both CERN and regional Tier-2 centres, while they export data to a global mesh of Tier-2s at rates comparable to the raw export data rate from CERN. The combined capacity of the Tier-1 centres is more than twice the resources located at CERN and efficiently utilizing this large distributed resources represents a challenge. In this article we will discuss the experience building, operating, and utilizing the CMS Tier-1 computing centres. We will summarize the facility challenges at the Tier-1s including the stable operations of CMS services, the ability to scale to large numbers of processing requests and large volumes of data, and the ability to provide custodial storage and high performance data serving. We will also present the operations experience utilizing the distributed Tier-1 centres from a distance: transferring data, submitting data serving requests, and submitting batch processing requests.

Original languageEnglish (US)
Article number072035
JournalJournal of Physics: Conference Series
Issue number1 PART 7
StatePublished - 2010
Event17th International Conference on Computing in High Energy and Nuclear Physics, CHEP 2009 - Prague, Czech Republic
Duration: Mar 21 2009Mar 27 2009

ASJC Scopus subject areas

  • General Physics and Astronomy


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