Enabling Grids for E-sciencE INFSO-RI-508833 Overview of experiences with LHC data challenges There was continual evolution throughout 2004, with LCG and experiments gaining more experience in the development and use of an expanding LCG grid All experiments had excellent relations with LCG-EIS support – a model for the future support of VOs Global job efficiencies ranged from 60-80% as experience developed – must get up to 90+% for user analysis - look to new middleware developments and tighter operational procedures Sources of problems and losses –Site configuration, management and stability –Data Management (especially metadata handling) –Difficult to monitor job running and causes of failure D0 in early 2005 showed that one can run with good efficiency with a set of well controlled sites
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