Information on the LHC Computing Grid (LCG) can be found here
. In particular, the LCG-2 User Guide can be very useful, if a little detailed. The best place to clear up what all that grid jargon means is the Grid Acronym Soup
. For a guide to getting started see the "Using the Grid" section of the ATLAS Workbook
To find out how to get a grid certificate and an ATLAS VO see:
Ganga is a grid interface for ATLAS and LHC.
- The main ganga web page is here
- For information on using ganga in ATLAS see here
- Simple setup instructions for ganga version 5 are here (the legacy page is here).
pAthena is an interface for the OSG, where jobs get sent to grid sites for analysis.
- One command will send a job off, and put your output in a DQ2 dataset. Your athena release area must be set up correctly, but it seems to be very efficient:
pathena <JobOptions>.py --inDS <inputdataset> --outDS user10.<nickname>.<outputname>
- Monitor your jobs by logging in here and going to your page
- Once the job is finished, just do
dq2_get -r user10.<nickname>.<outputname>
- See the UsingPathena page for full details.
The dq2 tool allows global access to atlas datasets stored on all flavours of the grid.
- For information on the dq2 tool see here
- For information on the dq2 end-user tools see here or here
- There is also a web-based dataset browser
Making datasets and registering them to DQ2
Making your locally stored files into a dataset which can be accessed from the grid is relatively simple. All you need to do is:
voms-proxy-init -voms atlas -valid 90:00
dq2-put -s <SOURCE-DIRECTORY> <DATASET-NAME>
1). Your dataset name must be unique and follow the naming rules (https://twiki.cern.ch/twiki/bin/view/Atlas/DQ2ClientsHowTo#DatasetNameRules
2). The individual file names should also be unique on the grid. Since you need an athena release to use the dq2-put command, you'll need to do this from one of the interactive nodes (alpha, theta etc) rather than hepgrid1.
3). I found that sourcing the Liverpool ATLAS grid setup script (/batchsoft/atlas/grid/setup.sh) gave an 'LFC exception: python bindings missing' error. Setting up dq2 only (i.e. without ganga and panda) worked for me, though maybe this was just a temporary glitch...
The Grid at Liverpool
- The grid user interface (UI) at Liverpool is hepgrid1. You can log on to this from any internal machine by doing
- The following variables set the LHC file catalog (LFC) to use and the default base directory for the LFC commands.
export LFC_HOST=lfc0448.gridpp.rl.ac.uk export LFC_HOME=/grid/atlas/datafiles/
- To use dq2 at Liverpool log on to the UI and do
- To get your files, do
voms-proxy-init -voms atlas -valid time in hours and minutes It then then asks for your password. Then do
dq2_get -r dataset files
- To use the latest version of ganga at Liverpool log on to the UI and do
source /batchsoft/atlas/grid/ganga/setup.sh To use an older version try
source /hepstore/store1/ganga/setup.sh < version > An example .gangarc file for atlas can be found at /hepstore/store1/ganga/ExampleGangaRC
- 02 May 2007