1. 27.05.2004Bernd Panzer-Steindel, CERN/IT WAN RAW/ESD Data Distribution for LHC

2. 27.05.2004Bernd Panzer-Steindel, CERN/IT 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

3. 27.05.2004Bernd Panzer-Steindel, CERN/IT 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 Network

4. 27.05.2004Bernd Panzer-Steindel, CERN/IT 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 !! modular layers simplicity performance

5. 27.05.2004Bernd Panzer-Steindel, CERN/IT Proposed timescales and scheduling MidyearEndyear 2004 10Gbit end-to-end tests with Fermilab First version of the LHC Community Network proposal 10Gbit end-to-end test complete with European Partner Measure performance variability and understand H/W and S/W Issues to ALL sites. Document circuit switched options and costs, first real test if possible. 2005 Circuit/Packet switch design completed. LHC Community network proposal completed. All T1 Fabric architecture documents completed. LCG TDR completed Sustained throughput test achieved to some sites: 2-4 Gb/sec for 2 months. H/W and S/W problems solved. 2006 All CERN b/w provisioned. All T1 bandwidth in production (10Gb links) Sustained throughput tests achieved to most sites. Verified performance to all sites for at least 2 months.

6. 27.05.2004Bernd Panzer-Steindel, CERN/IT 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………………………..