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Storage status & forecast

Storage status & forecast. Reminder of CM policy. RAW data CERN + one additional copy @ Tier1 Share based on CPU pledges for a given year SDST/FULL.DST Only latest reconstruction Prevents re-stripping former reconstruction Pass n-1 removed as soon as pass n starts Stream DST One archive

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Storage status & forecast

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  1. Storage status &forecast

  2. Reminder of CM policy • RAW data • CERN + one additional copy @ Tier1 • Share based on CPU pledges for a given year • SDST/FULL.DST • Only latest reconstruction • Prevents re-stripping former reconstruction • Pass n-1 removed as soon as pass n starts • Stream DST • One archive • Pass n: 4 replicas (CERN + 3) • Pass n-1: 2 replicas • Pass n-2: removed when pass n starts • Incremental stripping: 4 replicas, but should be <10% of n • MC DST • One archive • 3 replicas • How do we retire MC passes? NCB 26.11.2012, PhC

  3. Current tape status Collision12 Collision11 RAW CERN NCB 26.11.2012, PhC

  4. Tape crisis • As announced, tape is a real issue: • More data than expected: longer LHC run, higher HLT rate • Usage of FULL.DST instead of SDST • 5GB instead of 2 GB for a 3 GB RAW file • Mitigated by removing previous processing’s SDST • FULL.DST on disk until stripping is complete • Less stress on the tape cache disks • Mitigated by removing non-CERN archive of many datasets (now only one archive for all datasets) • Stopped archiving at GRIDKA, IN2P3, PIC and SARA • Sites have kindly agreed to let us use more than the pledge • RAL provides an additional 1 PB of tape • Other sites on best effort • Agreement between LHCb and ALICE for load of tapes • GRIDKA, CNAF if needed • SARA “very close” to the end NCB 26.11.2012, PhC

  5. Disk status MC11a Collision12 MC10 Collision12 Collision11 NCB 26.11.2012, PhC

  6. Situation w.r.t. pledges • CERN and CNAF: some disk ready to be installed • Part of tape cache not included for dCache sites • WARNING: decrease of requirements/pledges in 2013!! NCB 26.11.2012, PhC

  7. Pledges 2013 vs 2012 • 2012: 75.4% of requirements pledged • Requirements were mitigated and reviewed • 2013: new fraction at some Tier1s • When applied to a “reduced” requirement, decrease of pledges • Proposal: use 2012 fraction of pledges for 2013 • More inline w.r.t. 2012 pledges NCB 26.11.2012, PhC

  8. Tape staging • 2012: max of (prompt + reprocessing) • Repro 2012-2: current phase (lower pace) • Assuming 5 weeks for 2011 reprocessing • Lower pace than 2012 reprocessing • Restripping is the challenge for tape staging • Warn sites well in advance • Assign enough tape drives (less for writing) NCB 26.11.2012, PhC

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