ATLAS and Grid ATLAS and Grid ComputingComputing

RWL JonesGridPP 13 5th July 2005

ATLAS Computing ATLAS Computing TimelineTimeline

2003 • POOL/SEAL release (done)

• ATLAS release 7 (with POOL persistency) (done)

• LCG-1 deployment (done)

• ATLAS complete Geant4 validation (done)

• ATLAS release 8 (done)

• DC2 Phase 1: simulation production (done)

• DC2 Phase 2: intensive reconstruction (the real challenge!) LATE!

• Combined test beams (barrel wedge) (done)

• Computing Model paper (done)

• Computing Memorandum of Understanding (done)

• ATLAS Computing TDR and LCG TDR (in progress)

• Computing System Commissioning

• Physics Readiness Report

• Start cosmic ray run• GO!

2004

2005

2006

2007

NOW

Commissioningtakes priority!

Computing TDR Computing TDR structurestructure

The TDR describes the whole Software & Computing Project as defined within the ATLAS organization:

Major activity areas within the S&C Project

Liaisons to other ATLAS projects

Massive Massive productions on 3 productions on 3

GridsGrids

Massive Massive productions on 3 productions on 3

Grids (3)Grids (3)• July-September 2004: DC2 Geant-4 simulation (long

jobs)– 40% on LCG/EGEE Grid, 30% on Grid3 and 30% on NorduGrid

• February-May 2005: Rome production– 70% on LCG/EGEE Grid, 25% on Grid3, 5% on NorduGrid

• LCG/EGEE Grid resources always difficult to saturate with “traditional” means– New approach (Lexor-CondorG) used Condor-G to submit

directly to the sites• in this way the job rate was doubled on the same total available

resources – much more efficient usage of the CPU resources

– the same approach is now evaluated also for the Grid3/OSG Grid job submission which suffered also from job rate problems

Massive Massive productions on 3 productions on 3

Grids (4)Grids (4)• 73 data sets containing 6.1M events simulated and

reconstructed (without pile-up)• Total simulated data: 8.5M events• Pile-up done later (for 1.3M events done up to last week)

Number of Jobs

Grid324%

LCG34%

LCG-CG31%

NorduGrid11%

Grid3

LCG

LCG-CG

NorduGrid

ATLAS Rome Production - Number of Jobsuibk.ac.at triumf.caumomtreal.ca utoronto.cacern.ch unibe.chcsvs.ch golias.czskurut.cz gridka.fzk.deatlas.fzk.de lcg-gridka.fzk.debenedict.dk nbi.dkmorpheus.dk ific.uv.esft.uam.es ifae.esmarseille.fr cclcgcdli.in2p3.frclrece.in2p3.fr cea.frisabella.gr kfki.hucnaf.it lnl.it

roma1.it mi.itba.it pd.itlnf.it na.itto.it fi.itct.it ca.it

fe.it pd.itroma2.it bo.itpi.it sara.nl

nikhef.nl uio.nohypatia.no zeus.pllip.pt msu.ru

hagrid.se bluesmoke.sesigrid.se pdc.sechalmers.se brenta.sisavka.sk ihep.susinica.tw ral.ukshef.uk ox.ukucl.uk ic.uklancs.uk man.uked.uk UTA.us

BNL.us BU.usUC_ATLAS.us PDSF.us

FNAL.us IU.usOU.us PSU.us

Hamptom.us UNM.usUCSanDiego.us Uflorida.su

SMU.us CalTech.usANL.us UWMadison.usUC.us Rice.usUnknown

573315 jobs

22 countries

84 sites

Experience with Experience with LCG-2 OperationsLCG-2 Operations

• Support for our productions was excellent from the CERN-IT-EIS team

• Other LCG/EGEE structures were effectively invisible (GOC, ROCs, GGUS etc)– no communication line between experiments and the Grid

Operations Centres– operational trouble info always through the EIS group– sites scheduled major upgrades or downtimes during our

productions• no concept of “service” for the service providers yet!• many sites consider themselves as part of a test structure set up (and

funded) by EGEE• but we consider the LCG Grid as an operational service for us!

– many sites do not have the concept of “permanent disk storage” in a Storage Element

• if they change something in their filing system, our catalogue has to be updated!

Second ProdSys Second ProdSys development cycledevelopment cycle

• The experience with DC2 and the Rome production taught us that we had to re-think at least some of the ProdSys components

• The ProdSys review defined the way forward:– Frederic Brochu one of the reviewers– Keep the global ProdSys architecture (system decomposition)– Replace or re-work all individual components to address the

identified shortcomings of Grid middleware:• reliability and fault tolerance first of all

– Re-design the Distributed Data Management system to avoid single points of failure and scaling problems

• Work is now underway– target is end of Summer for integration tests– ready for LCG Service Challenge 3 from October onwards

Distributed Data Distributed Data ManagementManagement

• Accessing distributed data on the Grid is not a simple task

• Several central DBs are needed to hold dataset information

• “Local” catalogues hold information on local data storage

• The new DDM system(right) is under test this summer

• It will be usedfor all ATLAS datafrom October on(LCG ServiceChallenge 3)

• Affects GridPP effort

Computing Computing OperationsOperations

• The Computing Operations organization likely to change:a)Grid Tools

b)Grid operations: Tier-0 operations re-processing of real and simulated data at Tier-1's

data distribution and placement Software distribution and installation

Site and software installation validation and monitoring Coordination of Service Challenges in 2005-2006 User Support

Proposal to use Frederic Brochu in front-line triage Credited contribution Contingent on Distributed Analysis planning

Software Software InstallationInstallation

• Software installation continues to be a challenge– Rapid roll-out of release to the Grid important for

ATLAS UK eScience goals (3.1.4)– Vital for user code in distributed analysis

• Grigori Rybkine (50/50 GridPP/ATLAS eScience):– Working towards 3.1.5, kit installation and package

management in distributed analysis– Package manager implementation supports tarball

and locally-built code– Essential support role– 3.1.5 progressing well, 3.1.4 may have some delays

because of external effort in nightly deployable packages

Current plans Current plans for EGEE/gLitefor EGEE/gLite

• Ready to test new components as soon as they are released from the internal certification process– assume the LCG Baseline Services

• Only seen the File Transfer Service & LCG File Catalogue– both being actively tested by our DDM group

– FTS will be field-tested by Service Challenge 3 starting in July

– LFC is in our plan for the new DDM (Summer deployment)

• Not really seen the new Workload Management System nor the new Computing Element – some ATLAS informal access to pre-release versions

• As soon as the performance is acceptable we will ask to have them deployed– this is NOT a blank check!

Distributed Analysis Distributed Analysis SystemSystem

• ATLAS and GANGA work now focused on Distributed Analysis• LCG RTAG 11 in 2003 did not produce a common analysis system

project as hoped. ATLAS therefore planned to combine the strengths of various existing prototypes:– GANGA provides a Grid front-end for Gaudi/Athena jobs– DIAL provides fast, quasi-interactive, access to large local clusters– The ATLAS Production System to interface to the 3 Grid flavours

• Alvin Tan – Work on the job-building GUI and Job Options Editor well received

• Wish from LBL to merge JOE with Job Options Tracer project

– Monitoring work also well received – prototypes perform well.

• Frederic Brochu– Provided beta version of new job submission from GANGA direct to

Production System

Distributed Analysis Distributed Analysis System (2)System (2)

• Currently reviewing this activity to define a baseline for the development of start-up Distributed Analysis System– All this has to work together with the DDM

system described earlier– Decide a baseline “now”, so we can have a

testable system by this autumn– The outcome of the review may change

GridPP plans

ConclusionsConclusions

• ATLAS is (finally) getting effective throughput from LCG

• The UK effort is making an important contribution

• The Distributed Analysis is continuing to pose a big challenge– ATLAS is taking the right management

approach– GridPP effort will have to be responsive