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WAN RAW/ESD Data Distribution for LHC

WAN RAW/ESD Data Distribution for LHC. T0  T1 dataflow T0 Mass Storage recording of the RAW data from the 4 LHC experiments T0 First ESD production RAW data and ESD export to the Tier1 centers one copy of the RAW data spread over the T1 centers of an experiment

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WAN RAW/ESD Data Distribution for LHC

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  1. WAN RAW/ESD Data Distribution for LHC Bernd Panzer-Steindel, CERN/IT

  2. T0  T1 dataflow • T0 Mass Storage recording of the RAW data from the 4 LHC experiments • T0 First ESD production • RAW data and ESD export to the Tier1 centers one copy of the RAW data spread over the T1 centers of an experiment several copies of the ESD data sets (3-6), experiment dependent ESD size ~= 0.5 * RAW data (each T1 2/3 or one copy of the ESD)  ~10PB per year (requirements from the latest discussions with the 4 experiments) • T1T0 Data import (new ESD versions, MC data, AOD, etc.) • near real time export to the Tier1 centers during LHC running (200 days per year) + ALICE heavy ion data during the remaining 100 days • data transfers are between mass storage systems near real time == from disk cache  sizing of the tape system == minimal data recall from tape Bernd Panzer-Steindel, CERN/IT

  3. Network • There are currently 7+ Tier1 centers • (RAL, Fermilab, Brookhaven, Karlsruhe, IN2P3, CNAF, PIC,…) • The T0 export requirements need at least a 10 Gbit/s link per Tier1 • (plus more if one includes the Tier1-Tier2 communications) • The CERN T0 needs at least a 70 Gbit/s connection • the efficiency is still unknown Bernd Panzer-Steindel, CERN/IT

  4. We need to start Service Data Challenges which • should test/stress all necessary layers for these large continuous data • transfers • network hardware circuit switching versus packet switching, QoS • transport TCP/IP parameters, new implementations • transfer mechanisms GRIDFTP • mass storage systems ENSTORE, CASTOR, HPSS, etc. • coupling to the mass storage systems SRM 1.x • replication system • data movement service (control and bookkeeping layer) • Key points : • resilience and error-recovery !! • resilience and error-recovery !! • resilience and error-recovery !! • modular layers • simplicity • performance Bernd Panzer-Steindel, CERN/IT

  5. Proposed timescales and scheduling Bernd Panzer-Steindel, CERN/IT

  6. These WAN service data challenges needs dedication of • material : cpu server, disk server, tape drives , etc. • services : HSM, load balanced GRIDFTP, network • personnel : for running the DC, debugging, tuning, software selection and tests on the T0 and the different T1 centers dedication of material and personnel for longer time periods months not weeks ! important for getting the necessary experience, only 2 years for a reliable working system worldwide, T1 – T0 network to be watched : • interference with ongoing productions (HSM, WAN capacity, etc.) need to start now with a more detailed plan and start to ‘fill’ the network right now ! challenging, interesting and very important who is participating when and how ????? discussion……………………….. Bernd Panzer-Steindel, CERN/IT

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