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F Harris(Oxford) E van Herwijnen(CERN) G Patrick(RAL)

LHCb ‘use-case’ - distributed MC production http://lhcb-comp.web.cern.ch/lhcb-comp/grid/Default.htm. F Harris(Oxford) E van Herwijnen(CERN) G Patrick(RAL). Overview of presentation. The LHCb distributed MC production system Where can GRID technology help? - our requirements

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F Harris(Oxford) E van Herwijnen(CERN) G Patrick(RAL)

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  1. LHCb ‘use-case’ - distributed MC production http://lhcb-comp.web.cern.ch/lhcb-comp/grid/Default.htm F Harris(Oxford) E van Herwijnen(CERN) G Patrick(RAL) F Harris Datagrid Testbed meeting at Milan

  2. Overview of presentation • The LHCb distributed MC production system • Where can GRID technology help? - our requirements • Current production centres and GRID Testbeds F Harris Datagrid Testbed meeting at Milan

  3. LHCb working production system(and forward look to putting in GRID..) • Generate events • write log to Web • (globus-run) • copy to mass store • Globus-rcp,gsi-ftp • call servlet (at CERN) Construct job script and submit via Web (remote or local at CERN) (GRID Certification) mass store (e.g. RAL Atlas data store, CERN shift system) • Get token on shd18 • (Certification) • copy data to shift • copy data to tape • (gsi-ftp) CERN or remote • Find next free tape-slot • call servlet to copy data from mass store to tape at CERN • update bookkeeping db • (Oracle) CERN only F Harris Datagrid Testbed meeting at Milan

  4. Problems of production system Main issue: • We are forced to copy all data back to CERN Reasons for this: • Standard cataloguing tools do not exist - so we cannot keep track of the data where it is produced • Absence of smart analysis job-submission tools that move executables to where the input data is stored Steps that make the production difficult: • Authorisation (jobs can be submitted only from trusted machines) • Copy data (generated both inside & outside CERN) into the CERN mass store (many fragile steps) • Updating of the bookkeeping database at CERN (Oracle interface is non standard) F Harris Datagrid Testbed meeting at Milan

  5. Where can the GRID help? • Very transparent way of authorizing users on remote computers • data set cataloguing tools (LHCb has expertise and is willing to share experience) to avoid unnecessary replication • if replication is required, provide fast and reliable tools • analysis job submission tools • interrogate the data set catalogue and specify where the job should be run; (the executable may need to be sent to the data) • read different datasets from different sites into interactive application • standard/interface for submitting/monitoring production jobs on any node on the GRID F Harris Datagrid Testbed meeting at Milan

  6. Current and ‘imminent’ production centres CERN • Samples (several channels) for Trigger TDR on PCSF (~10**6 events) RAL • 50k 411400 (Bd-> J/psi K (e+e-), DST2, for Trigger • 250k inclusive bbar + 250k mbias RAWH, DST2, no cuts Liverpool • 2 million MDST2 events after L0 and L1 cuts Lyon • plan to do 250 k inclusive bb-bar events without cuts (January) Nikhef and Bologna • Will generate samples for Detector and Trigger studies (? Mar/April) F Harris Datagrid Testbed meeting at Milan

  7. Exists Planned Initial LHCb-UK GRID “Testbed” CERN pcrd25.cern.ch lxplus009.cern.ch RAL CSF 120 Linux cpu IBM 3494 tape robot Institutes LIVERPOOL MAP 300 Linux cpu RAL (PPD) Bristol RAL DataGrid Testbed Imperial College GLASGOW/ EDINBURGH “Proto-Tier 2” Oxford F Harris Datagrid Testbed meeting at Milan

  8. Initial Architecture • Based around existing production facilities (separate Datagrid testbed facilities will eventually exist). • Intel PCs running Linux Redhat 6.1 • Mixture of batch systems (LSF at CERN, PBS at RAL, FCS at MAP). • Globus 1.1.3 everywhere. • Standard file transfer tools (eg. globus-rcp, GSIFTP). • GASS servers for secondary storage? • Java tools for controlling production, bookkeeping, etc. • MDS/LDAP for bookkeeping database(s). F Harris Datagrid Testbed meeting at Milan

  9. Other LHCb countries(and institutes) developing Tier1/2/3 centres and GRID plans • Germany,Poland,Spain,Switzerland,Russia • see talk at WP8 meeting of Nov 16 • Several institutes have installed Globus, or are about to (UK institutes,Clermont Ferrand,Marseille,Bologna,Santiago……) F Harris Datagrid Testbed meeting at Milan

  10. SuperJANET Backbone SuperJANET III 155 Mbit/s (SuperJANET IV 2.5Gbit/s) London Networking Bottlenecks? Need to study/measure for data transfer and replication within UK and to CERN. RAL 34 Mbit/s 155 Mbit/s MAN MAN 622 Mbit/s (March 2001) 622 Mbit/s Campus 100 Mbit/s CERN Univ. Dept TEN-155 Schematic only

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