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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 - PowerPoint PPT Presentation
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LHCb
Storage status &forecast
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Reminder of CM policy
m RAW datao CERN + one additional copy @ Tier1
P Share based on CPU pledges for a given yearm SDST/FULL.DST
o Only latest reconstructionP Prevents re-stripping former reconstruction
o Pass n-1 removed as soon as pass n startsm Stream DST
o One archiveo Pass n: 4 replicas (CERN + 3)o Pass n-1: 2 replicaso Pass n-2: removed when pass n startso Incremental stripping: 4 replicas, but should be
<10% of nm MC DST
o One archiveo 3 replicaso How do we retire MC passes?
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Current tape status
Collision12
Collision11
RAW CERN
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Tape crisis
m As announced, tape is a real issue:o More data than expected: longer LHC run, higher HLT
rateo Usage of FULL.DST instead of SDST
P 5 GB instead of 2 GB for a 3 GB RAW fileP Mitigated by removing previous processing’s SDSTP FULL.DST on disk until stripping is complete
d Less stress on the tape cache disksm Mitigated by removing non-CERN archive of many
datasets (now only one archive for all datasets)o Stopped archiving at GRIDKA, IN2P3, PIC and SARA
m Sites have kindly agreed to let us use more than the pledge
o RAL provides an additional 1 PB of tapeo Other sites on best efforto Agreement between LHCb and ALICE for load of
tapesP GRIDKA, CNAF if needed
o SARA “very close” to the end
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Disk status
Collision12
Collision11
MC11aMC10
Collision12
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Situation w.r.t. pledges
m CERN and CNAF: some disk ready to be installedm Part of tape cache not included for dCache sitesm WARNING: decrease of requirements/pledges in
2013!!
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Pledges 2013 vs 2012
m 2012: 75.4% of requirements pledgedo Requirements were mitigated and reviewed
m 2013: new fraction at some Tier1so When applied to a “reduced” requirement, decrease
of pledgeso Proposal: use 2012 fraction of pledges for 2013
P More inline w.r.t. 2012 pledges
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NCB 26.11.2012, PhC 8
Tape staging
m 2012: max of (prompt + reprocessing)o Repro 2012-2: current phase (lower pace)
m Assuming 5 weeks for 2011 reprocessingo Lower pace than 2012 reprocessing
m Restripping is the challenge for tape stagingo Warn sites well in advanceo Assign enough tape drives (less for writing)
