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LCG-France sites contribution to the LHC activities in 2007

LCG-France sites contribution to the LHC activities in 2007. A.Tsaregorodtsev, CPPM, Marseille. 14 January 2008, LCG-France Direction. Outline. LHCb activities in 2007 T1 contribution T2 contributions Conclusion. LHCb activities in 2007. MC production

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LCG-France sites contribution to the LHC activities in 2007

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  1. LCG-France sites contribution to the LHC activities in 2007 A.Tsaregorodtsev, CPPM, Marseille 14 January 2008, LCG-France Direction

  2. Outline • LHCb activities in 2007 • T1 contribution • T2 contributions • Conclusion

  3. LHCb activities in 2007 • MC production • Limited, more emphasis on data reprocessing and analysis • Not evenly distributed over the year • Working on physicist’s requests • ~400M events produced • ~100TB data stored • Data distribution • DST and DIGI data to all the T1 centers • First tests done with SRM2.2 end-points • FTS transfers

  4. LHCb activities in 2007 • Data reconstruction and filtering (stripping) • Done in the T1 centers • Lots of difficulties with data access in the Storage systems • Migration of sites to SLC4 created quite a lot of problems • Storing and accessing data • Bugs in the middleware, incompatibility with the LHCb software stack (python versions, 32-64 bit platforms sw mixture, etc) • Depends on versions of the reconstruction and analysis applications • User analysis • Done in the T1 centers • Low activity at the beginning of 2007 • High in the end • CERN batch queues are overloaded • Analysis spills over to other T1 centers

  5. T1 resources contribution by LCG-France • CC/IN2P3 actively participated in all the LHCb activities • CC/IN2P3 resources provided • 15 MUI (87M SI2K) • ~50% of the 2007 request • 6.4% of the total LHCb resources • 16% of the total LHCb T1 resources ( including CERN ) • 1160M SI2K requested for 2008 • ~18% of the LHCb total (T1+T2) • Total 35K production jobs

  6. T1 resources contribution by LCG-France • ~30% of jobs through local batch system access via DIRAC Job Agent in the beginning 2008 • Now ~100% grid access • Job efficiency • High for MC production jobs • Low (~65%) for reconstruction jobs needing access to data • Data reconstruction at T1/IN2P3 • Progressing with difficulties • Smoother at CC/IN2P3 than at other sites

  7. Data storage at T1 • Disk storage • 62TB stored on disks (18% of the LHCb T1 total) • 103 TB requested for 2007 • Disk storage provisioning was in time for 2007 • 280 TB required in 2008 • Tape storage • 18TB stored in HPSS ( ~8 % of the LHCb T1 total) • No problem with provisioning • 230 TB required in 2008

  8. Data access at T1 • Data access is problematic • Many failures due to lost connections to the data • Several periods where data access was completely impossible • Situation not unique to CC/IN2P3 • The dCache access is suffering problems right now • Access to data on tapes needs prestaging before the jobs are submitted • Special service developed in the LHCb DIRAC WMS • Data management operations are slow • Clean-up of the disk storage takes weeks • Needs intervention of the local managers • Difficult and slow to remove data through standard service interfaces

  9. User analysis at T1 • Progressively increasing • 57K total LCG jobs in November 2007 • 7140 in CC/IN2P3 (12.5% of the total) • Long periods with ~1000 concurrent jobs • Highly depends on the steady functioning of the Storage Elements • Can not distribute all the data everywhere • Some data unavailable if an SE suffering problems • No preference for accessing national resources by local users • Advantageous especially when resources access is unstable

  10. User analysis jobs • Number of analysis jobs in LHCb as a whole • Analysis jobs at CC/IN2P3

  11. LHCb services at T1 center a Lyon • FTS • Configured for the SRM2.2 end-point • Tests are OK • LHCb VO-box • An instance of the Configuration Services • Request Database supporting the DIRAC failover mechanisms • LCG File Catalog instance • A mirror of the Master instance at CERN • Automatic metadata replication with ORACLE streams • Operational since December 2007 • Important service for the CCRC’08

  12. T2 resources contribution by LCG-France • Tier2-Tier3 contributions to LHCb resources

  13. T2 resources contribution by LCG-France • Total of the T2-T3 LHCb contribution - 3.7% • Low because of limited MC production in 2007 • T2 LCG-France LHCb resources are small • Job distribution via LCG WMS brokers • Low ranking of the relatively small french T2 sites • Mostly MC production • Small fraction of user toy MC jobs • High efficiency rate close to 100% • No input data

  14. Summary • 2007 was a rather difficult year with many problems to solve due to a rapid middleware and software evolution • SLC4, gLite, SRM2.2, applications, etc • Data production is affected by the data access problems • Resources consumption is determined by the amount of data possible to reprocess • No special quotas reserved for the french users on the LCG-France resources: • Similar to policies for other national resources • LHCb policies are defined by group activities • Good support for the LHCb activities by the contact persons

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