CHEP – Mumbai, February 2006 The LCG Service Challenges Focus on SC3 Re-run; Outlook for 2006 Jamie Shiers, LCG Service Manager

Abstract  The LCG Service Challenges are aimed at achieving the goal of a production quality world-wide Grid that meets the requirements of the LHC experiments in terms of functionality and scale.  This talk highlights the main goals of the Service Challenge programme, significant milestones as well as the key services that have been validated in production by the LHC experiments.  The LCG Service Challenge programme currently involves both the 4 LHC experiments as well as many sites, including the Tier0, all Tier1s as well as a number of key Tier2s, allowing all primary data flows to be demonstrated.  The functionality so far addresses all primary offline Use Cases of the experiments except for analysis, the latter being addressed in the final challenge - scheduled to run from April until September prior to delivery of the full production Worldwide LHC Computing Service.

Timeline JanuarySC3 disk repeat – nominal rates capped at 150MB/s JulyTape Throughput tests at full nominal rates! FebruaryCHEP w/s – T1-T1 Use Cases, SC3 disk – tape repeat (50MB/s, 5 drives) AugustT2 Milestones – debugging of tape results if needed MarchDetailed plan for SC4 service agreed (M/W + DM service enhancements) SeptemberLHCC review – rerun of tape tests if required? AprilSC4 disk – disk (nominal) and disk – tape (reduced) throughput tests OctoberWLCG Service Officially opened. Capacity continues to build up. MayDeployment of new m/w release and services across sites November1 st WLCG ‘conference’ All sites have network / tape h/w in production(?) JuneStart of SC4 production Tests by experiments of ‘T1 Use Cases’ ‘Tier2 workshop’ – identification of key Use Cases and Milestones for T2 December‘Final’ service / middleware review leading to early 2007 upgrades for LHC data taking?? O/S Upgrade? Sometime before April 2007!

SC3 -> SC4 Schedule  February 2006  Rerun of SC3 disk – disk transfers (max 150MB/s X 7 days)  Transfers with FTD, either triggered via AliEn jobs or scheduled  T0 -> T1 (CCIN2P3, CNAF, Grid.Ka, RAL)  March 2006  T0-T1 “loop-back” tests at 2 x nominal rate (CERN)  Run bulk T1,T2 (simulation+reconstruction jobs) and send data back to CERN  (We get ready with  April 2006  T0-T1 disk-disk (nominal rates) disk-tape (50-75MB/s)  First Push out (T0 -> T1) of simulated data, reconstruction at T1  (First tests with  July 2006  T0-T1 disk-tape (nominal rates)  T1-T1, T1-T2, T2-T1 and other rates TBD according to CTDRs  Second chance to push out the data  Reconstruction at CERN and remote centres  September 2006  Scheduled analysis challenge  Unscheduled challenge (target T2’s?)

June “Tier2” Workshop  Focus on analysis Use Cases and Tier2s in particular  List of Tier2s reasonably well established  Try to attract as many as possible!  Need experiments to help broadcast information on this!  Some 20+ already active – target of 40 by September 2006!  Still many to bring up to speed – re-use experience of existing sites!  Important to understand key data flows  How experiments will decide which data goes where  Where does a Tier2 archive its MC data?  Where does it download the relevant Analysis data?  The models have evolved significantly over the past year!  Two-three day workshop followed by 1-2 days of tutorials Bringing remaining sites into play: Identifying remaining Use Cases

Track on Distributed Data Analysis DIAL ProdSys BOSS Ganga Analysis Systems PROOF CRAB Submission Systems DIRAC PANDA Bookkeeping Systems JobMon BOSS BbK Monitoring Systems DashBoard JobMon BOSS MonaLisa Data Access Systems xrootd SAM Miscellaneous Go4 ARDA Grid Simulations AJAX Analysis

Data Analysis Systems ALICEATLASCMSLHCb PROOFDIAL GANGA CRAB PROOF GANGA  All systems support, or plan to support, parallelism  Except for PROOF all systems achieve parallelism via job splitting and serial batch submission (job level parallelism)  The different analysis systems presented, categorized by experiment:

Classical Parallel Data Analysis Storage Batch farm queues manager outputs catalog  “Static” use of resources  Jobs frozen, 1 job / CPU  “Manual” splitting, merging  Limited monitoring (end of single job)  Possible large tail effects submit files jobs data file splitting myAna.C merging final analysis query From PROOF System by Ganis [98]

Interactive Parallel Data Analysis catalog Storage Interactive farm scheduler query  Farm perceived as extension of local PC  More dynamic use of resources  Automated splitting and merging  Real time feedback  Much better control of tail effects MASTER query: data file list, myAna.C files final outputs (merged) feedbacks (merged) From PROOF System by Ganis [98]