The grid STEPs up
Tue 2 Jun 2009
LHC restart is scheduled for later this year. With collisions will come massive amounts of data and also lots of new users. What effect will this have on the grid, can it cope? Starting today the LHC experiments are testing this with STEP09.
STEP09 (Scale Testing for the Experiment Program) is the combined efforts of the LHC experiment to challenge the computing models and infrastructure. The tests are running for the next two weeks, from the 2nd of June to the 14th and they will simulate real, full time use of the grid by all four experiments. It will be running all four experiments simultaneously and is a complete full dress rehearsal for data taking later in the year.
For the experiments this means they will be simulating the life cycle of physics data, from electronic signals within the detectors to a fully analysed and reconstructed particle. For ATLAS, the biggest experiment here in the UK, they are testing the entire offline computing model. It is a suite of intensive tests using all production tasks (reconstruction, simulation etc) and two forms of analysis at the same time. Importantly both pilot jobs and brokered jobs will be used.
LHCb will be taking part in STEP09 as a part of their own normally scheduled test of the computing system FEST'09 (FEST - Full Experiment System Test). For STEP09 they will be replicating conditions at all LHCb computing sites, that they expect during a steady running period. This will require simulating data taking conditions in the detector, transfer of this to the Tier-0, distribution to the Tier-1s and then analysis of it. Within CMS the tests will be looking at the data record rate at the Tier-0, the ability of the Tier-1's to archive and process data at the necessary rates and whether the Tier-2's are able to analyse the work at the speeds required by a full up and running LHC.
There is more technical information about what each experiment is doing at the following pages:
ATLAS - https://twiki.cern.ch/twiki/bin/view/Atlas/Step09
LHCb - http://lblogbook.cern.ch/FEST/
CMS - http://twiki.cern.ch/twiki/bin/view/CMS/Step09
© Copyright GridPP
If you wish to reproduce this piece please credit GridPP and contact Neasan O'Neill to say you are using it