Retrieving MC output

Outputs from Monte Carlo simulation are stored on disk at RAL and CERN. This page explains how to access this data.

CERN CASTOR

MC production data is transferred to CERN CASTOR via

srm://srm-public.cern.ch:8443/srm/managerv2

and accessible locally on

/castor/cern.ch/grid/na62/mc

e.g.

lxplus> nsls /castor/cern.ch/grid/na62/mc
prod
protopop
test

Other replicas

To find replicas for a given file, consult this table. Each expanded row will show the following information:

To find other replicas, use the commands

export LFC_HOST="lfc00.grid.hep.ph.ic.ac.uk"
lcg-lr LFN

where LFN is something that look like this lfn:/grid/na62.vo.gridpp.ac.uk/prod/v0.9.0/Kch2pienu-2/pluto_v14_r27792.root (see above).

Please note that LFC will soon be deprecated and this might not work for long.

Retrieving a file from a remote SE

If you have the LFN or the SRM of a file, the you can use lcg-cp to copy it to your local machine, e.g.

lcg-cp -v srm://svr018.gla.scotgrid.ac.uk/dpm/gla.scotgrid.ac.uk/home/na62.vo.gridpp.ac.uk/prod/r722/Kch2pipi0pi0/pluto_v13_r27584.root ./pluto_v13_r27584.root
lcg-cp -v lfn:/grid/na62.vo.gridpp.ac.uk/prod/v0.9.0/Kch2pienu-2/pluto_v14_r27792.root pluto_v14_r27792.root

Please remember that in order to use the above grid commands, you must have a valid proxy. To create one, do

voms-proxy-init  -voms na62.vo.gridpp.ac.uk

assuming you have a valid grid certificate (i.e. files usercert.pem and userkey.pem in ~/.globus/).

If you see the error message

VOMS server for VO na62.vo.gridpp.ac.uk is not known! Check your vomses configuration.

then you need to add the NA62 VO to your vomses configuration:

lxplus> ls ~/.glite/vomses
na62.vo.gridpp.ac.uk-voms02.gridpp.ac.uk  na62.vo.gridpp.ac.uk-voms03.gridpp.ac.uk  na62.vo.gridpp.ac.uk-voms.gridpp.ac.uk

lxplus> cat ~/.glite/vomses/na62.vo.gridpp.ac.uk-voms*
"na62.vo.gridpp.ac.uk" "voms02.gridpp.ac.uk" "15501" "/C=UK/O=eScience/OU=Oxford/L=OeSC/CN=voms02.gridpp.ac.uk" "na62.vo.gridpp.ac.uk"
"na62.vo.gridpp.ac.uk" "voms03.gridpp.ac.uk" "15501" "/C=UK/O=eScience/OU=Imperial/L=Physics/CN=voms03.gridpp.ac.uk" "na62.vo.gridpp.ac.uk"
"na62.vo.gridpp.ac.uk" "voms.gridpp.ac.uk" "15501" "/C=UK/O=eScience/OU=Manchester/L=HEP/CN=voms.gridpp.ac.uk" "na62.vo.gridpp.ac.uk"

With this setup, voms-proxy-init  -voms na62.vo.gridpp.ac.uk should work. If not, please contact the grid admin.

Glossary

Abbreviations used above:

• VO - virtual organisation, e.g. the NA62 VO is called na62.vo.gridpp.ac.uk
• SE - storage element: disk space at a given Grid site
• LFC - Logical File Catalogue
• LFN - logical file name: the name of the file in a given LFC
• VOMS - Virtual Organization Membership Service
• SRM - Storage Resource Management