Speaker
Johannes Elmsheuser
(Ludwig-Maximilians-Universität München)
Description
The distributed data analysis using Grid resources is one of the
fundamental applications in high energy physics to be addressed
and realized before the start of LHC data taking. The needs to
manage the resources are very high. In every experiment up to a
thousand physicist will be submitting analysis jobs into the Grid.
Appropriate user interfaces and helper applications have to be
made available to assure that all users can use the Grid without
expertise in Grid technology. These tools enlarge the
number of grid users from a few production administrators to
potentially all participating physicists.
The GANGA job management system (http://cern.ch/ganga), developed
as a common project between the ATLAS and LHCb experiments
provides and integrates these kind of tools.
GANGA provides a simple and consistent way of preparing,
organizing and executing analysis tasks within the experiment
analysis framework, implemented through a plug-in system. It allows
trivial switching between running test jobs on a local batch system
and running large-scale analyzes on the Grid, hiding Grid
technicalities.
We will be reporting on the plug-ins and our experiences of
distributed data analysis using GANGA within the ATLAS experiment.
Support for all grids presently used by ATLAS, namely the
LCG/EGEE, NDGF/NorduGrid, and OSG/PanDA is provided. The
integration and interaction with the ATLAS data management system
DQ2 into GANGA is a key functionality. An intelligent job
brokering is setup by using the job splitting
mechanism together with dataset and file location knowledge.
The brokering is aided by an automated system that regularly
processes test analysis jobs at all ATLAS DQ2 supported sites.
Large amounts of analysis jobs can be sent to the locations of
data following the ATLAS computing model.
GANGA supports amongst other things tasks of user analysis with
reconstructed data and small scale production of Monte Carlo data.
Author
Johannes Elmsheuser
(Ludwig-Maximilians-Universität München)
Co-authors
Alexander Soroko
(University of Oxford)
Andrew Maier
(CERN)
Benjamin Gaidioz
(CERN)
Bjorn Samset
(University of Oslo)
Daniel van der Ster
(CERN)
Frederic Brochu
(University of Cambridge)
Greig Cowan
(University of Edinburgh)
Hurng-Chun Lee
(NIKHEF)
Jakub Moscicki
(CERN)
Katarina Pajchel
(University of Oslo)
Mark Slater
(University of Birmingham)
Michael Williams
(Imperial College London)
Ulrik Egede
(Imperial College London)
Will Reece
(Imperial College London)
