Configuration: Basics

Introduction

CRAB is configured by a configuration file called crab.cfg. The configuration file should be located within the CMSSW user project directory at the same location as the CMSSW parameter-set to be used by CRAB. It's basic content is described in the following.

Basic crab.cfg

The minimal CRAB configuration file has the following content:

[CRAB]
jobtype                = cmssw
scheduler              = edg 

[CMSSW]

datasetpath            = /RelVal120Higgs-ZZ-4Mu/FEVT/CMSSW_1_2_0-FEVT-1166242770
pset                   = io.cfg

total_number_of_events = 100
events_per_job         = 10

output_file            = output.root

[USER]
return_data            = 1

use_central_bossDB     = 0

use_boss_rt            = 0

[EDG]
lcg_version            = 2
rb                     = CERN
proxy_server           = myproxy.cern.ch 
virtual_organization   = cms
retry_count            = 2
lcg_catalog_type       = lfc
lfc_host               = lfc-cms-test.cern.ch
lfc_home               = /grid/cms

The CRAB configuration file is structured into sections and it is important in which section a specific configuration item is listed. The section in the configuration file given above are

[CRAB]
[CMSSW]
[USER]
[EDG]

Basic parameters

[CRAB] section

[CMSSW] section

Parameter	Description
datasetpath	The datasetpath identifies the dataset you want to access. It can be queried by using the CMS data discovery page: http://cmsdbs.cern.ch/discovery/. More information is given at Dataset discovery and job configuration.
pset	The name of the CMSSW parameter-set of your CMSSW job. The parameter-set has to be in the same directory as the CRAB configuration file.
total_number_of_events	Total number of events to be processed by CRAB. If set to -1, all events of the selected dataset are processed. More information is given at Dataset discovery and job configuration.
events_per_job	Number of events per job. CRAB will create as many jobs as needed to process the total_number_of_events. Due to technical reasons, the number of jobs may be larger than the mathematical number of jobs (total_number_of_events/events_per_job) due to constraints for the job splitting. More information is given at Dataset discovery and job configuration.
outputfile	Comma-separated list of output filenames. Usually the filename selected in the PoolOutputSoure of the CMSSW parameter-set but can also hold user-specific output filenames like histogram files, etc. . These name is used by CRAB when generating the output filenames of the individual jobs. CRAB automatically adds job identifiers to the output filenames of the individual jobs so that the user can distinguish them. For example, if the output filename is output.root and the selected CRAB configuration results in 10 jobs, the output filenames of the individual jobs are named: output_00001.root, output_00002.root, ...

[USER] section

[EDG] section