Atlas:Analysis HC beyond STEP09

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--Chollet 15:56, 19 octobre 2009 (CEST)

Distributed Analysis Stress Tests - HammerCloud beyond STEP09

Lessons learnt from STEP09

  • Sites may identify reasonable amount of analysis they can assume and set hard limits on number of analysis running jobs
  • Balancing data across many disk servers is essential.
  • Very high i/o required by analysis (5 MB/s per job). Sites should review LAN architecture to avoid bottlenecks.


ATLAS Info & Contacts

  • Information via mailing list
  • LPC : Nabil Ghodbane -
  • LAL : Nicolas Makovec
  • LAPP : Stéphane Jézéquel
  • CPPM : Emmanuel Le Guirriec
  • LPSC : Sabine Crepe
  • LPNHE : Tristan Beau
  • CC-T2 : Catherine, Ghita
  • IRFU : Nathalie Besson

HC Tests



  • Improve Cloud readiness by following site&ATLAS problems week by week (SL5 migration, site upgrades)
  • Identify best data access method per site by comparing the event rate and CPU/Walltime

  • Exercise Analysis with Conditions DB access (see where squid caching is needed) and Tag analysis

Data Access methods

Multiple data access methods are exercised

  • via Panda : A copy-to-WN access mode using rfcp is used (xrootd in ANALY-LYON)
  • via gLite WMS : 2 data access modes available
    • DQ2_LOCAL mode is a direct access mode using rfio or dcap
    • FILE_STAGER mode : data staged in by a dedicated thread running in // with Athena

Week 40

29/09/09 Test 649

  Bad efficiency - all sites affected all sites 
  Failed jobs with error : exit code 1137
  Put error: Error in copying the file from job workdir to localSE
  due to LFC ACL problem : write permissions in /grid/atlas/users/pathena
  for pilot jobs /atlas/Role=pilot and /atlas/fr/Role=pilot (newly activated)

30/09/09 Test 652, 653, 656, 657

Week 41

08/10/09 Test 663

  • DPD Analysis (Release 15.5.0)
  • Input DS - DATADISK : data09_cos.*.DPD*
  • Cond DB access to Oracle in Lyon T1
  • via Panda (mode copy-to-WN using ddcp/rfcp - xrootd in ANALY-LYON)
  • Sites problems or downtime :
    • LAL : downtime
    • RO : DS unavailable
    • LYON (T2) : release 15.5.0 unavalaible
  Poor performance for foreign sites : Tokyo and Beijing compared to other french sites

Recent talks