Experience Building and Operating the CMS Tier-1 Computing Centers
Presented by Claudio GRANDI on 23 Mar 2009 from 08:00 to 08:20
Session: Poster session
Track: Distributed Processing and Analysis
Board #: Monday 060
The CMS Collaboration relies on 7 globally distributed Tier-1 computing centers located at large universities 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 centers 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 centers, 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 centers is more than twice the resources located at CERN and efficiently utilizing this large distributed resources represents a challenge. In this presentation we will discuss the experience building, operating, and utilizing the CMS TIer-1 computing centers. 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 centers from a distance: transferring data, submitting data serving requests, and submitting batch processing requests.