Site Support Team - Documentation
Xrootd Useful Information

Here you will find a list of twikis and commands to help you understand and troubleshoot Xrootd issues.

1. General Info and Guides
   • Operations Guide
   • Troubleshooting Guide
2. Instructions for Admins (Setup):
   • https://twiki.cern.ch/twiki/bin/view/Main/CmsXrootdArchitecture#For_Admins
3. List of Redirectors (hierarchical order):
   1. Global:
      • CERN
   2. Regional:
      • Nebraska/FNAL (US)
      • Paris/Bari/Pisa (Europe)
      • Beijing (Asia)
   3. Local
   4. Servers
4. Monitoring Tests for Xrootd Infrastructure
   • https://twiki.cern.ch/twiki/bin/view/Main/XrootdMonitoring
5. TFC Changes necessary for Xrootd
   • https://twiki.cern.ch/twiki/bin/view/Main/XrootdTfcChanges
6. Configuring Fallback Access
   • https://twiki.cern.ch/twiki/bin/view/Main/ConfiguringFallback
7. xrootd-access and xrootd-fallback status of all Sites
   • http://dashb-cms-sum.cern.ch/dashboard/request.py/latestresultssmry-sum#profile=CMS_CRITICAL_FULL&group=AllGroups&site%5B%5D=All+Sites&flavour%5B%5D=All+Service+Flavours&metric%5B%5D=org.cms.WN-xrootd-access&metric%5B%5D=org.cms.WN-xrootd-fallback&status%5B%5D=All+Exit+Status
8. Link to test the mapping of a test file:
   • https://cmsweb.cern.ch/phedex/datasvc/json/prod/lfn2pfn?node=T2_AT_Vienna&lfn=/store/test/xrootd/T2_AT_Vienna/store/mc/SAM/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0013/CE4D66EB-5AAE-E111-96D6-003048D37524.root&protocol=srmv2
     • The line "pfn:" should start with "srm:" and then the path configured in the storage.xml of the Site.
9. Contact the redirector and verify if the cmsd is integrated properly with the rest of the federation.

   • The best way to check, if you know their xrootd endpoint:
     xrdcp -d 1 -f root://$HOSTNAME//store/mc/SAM/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0013/CE4D66EB-5AAE-E111-96D6-003048D37524.root - > /dev/null
     
     The following should also work:
     xrdcp -d 1 -f r root://cms-xrd-global.cern.ch//store/test/xrootd/$SITENAME//store/mc/SAM/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0013/CE4D66EB-5AAE-E111-96D6-003048D37524.root - > /dev/null
     

10. Verify that the xrootd configuration of a site is working by accessing directly from the global redirector

    • access lxplus
      source /afs/cern.ch/cms/LCG/LCG-2/UI/cms_ui_env.sh
      voms-proxy-init -voms cms
      
      xrd cms-xrd-global.cern.ch
      help [to list available commands]
      
      existdir /store/test/xrootd/ [to check if directory exists]
      dirlist /store/test/xrootd/ [to list all directories with that path]
      
      [to check if a specific file exists]
      existfile /store/test/xrootd/T2_US_Florida/store/mc/SAM/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0013/CE4D66EB-5AAE-E111-96D6-003048D37524.root