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FZU participation in the Tier0 test

FZU participation in the Tier0 test. CERN August 3, 2006. Preparation. Data transfers via FTS tested using CERN FTS (April 2006). Preparation. Channel FZK-FZU created and tested. Good performance for FZU -> FZK, problems for FZK -> FZU. FZK cloud plans Tests in the week 5.-9.6.

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FZU participation in the Tier0 test

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  1. FZU participation in the Tier0 test CERN August 3, 2006 chudoba@fzu.cz

  2. Preparation Data transfers via FTS tested using CERN FTS (April 2006) chudoba@fzu.cz

  3. Preparation • Channel FZK-FZU created and tested. Good performance for FZU -> FZK, problems for FZK -> FZU. FZK cloud plans • Tests in the week 5.-9.6. • Each day 1 Tier2 site to test transfers initiated from Tier2, admins from Tier1 available to assist • Once we all have working transferes we could try a simultaneous T1-> All T2's and All T2's -> T1. This could be done over 1 or 2 days. Results • Basic functionality worked • Many problems with performance, stability, site’s availability chudoba@fzu.cz

  4. Example of achieved rates Wednesday 7.6. • 200GB from FZU to FZK via FTS request • Results next day: Done: 92 Hold: 108 Errors: • 25 transfers failed due to my mistake - target file already existed. • 82 Transfer timed out • 1 TRANSFER Operation Timed out During earlier tests the channel FZU – FZK achieved almost 100 Mbytes/s Limited not by network (iperf measurement was done), but by disk servers See wiki pages https://twiki.cern.ch/twiki/bin/view/Main/PragueAndServiceChallenge4ThroughputTests chudoba@fzu.cz

  5. Tier0 exercise • Only datasets copied to FZK were available for FZU • Started 19.6. • 19.6. – 20.6. scheduled downtime at FZK for mw upgrade, later extended to 21.6. evening • 21.6. – CERN – FZK transfers submitted to FTS server at CERN were still ending in the CERN-CERN channel • Which dataset to use? Looking for complete datasets available at FZK: dq2 listDatasetsInSite -c FZKTAPE • 22.6. first subscriptions to FZU (T0.D.run000831.RAW): • Did not succeed • 23.6. (Friday), 17:00: 3 complete datasets at FZKTAPE • 26.6. Fetchers for Tier2’s added to FZK vobox chudoba@fzu.cz

  6. 26.6. first files copied from FZK to FZU using DQ2 • Dataset with RAW data, big files 1.9 GB • 23 Gbytes transferred in 1 hour • Only 4 files copied, the rest timed out during transfer (FTS and disk servers problem), the remaining traffic due to retrials Later a few subscriptions FZK -> FZU, AOD datasets, sometimes failed due to missing source files (automatic deletion after 12 hours) chudoba@fzu.cz

  7. FTS tests FZK - FZU • Transfer of 50 files, each file 1GB • Starts fast, then timeouts occur: • Transfer of 100 files, each file 1GB • Started when load on Tier1 disk servers low chudoba@fzu.cz

  8. Conclusions • We managed to copy a few datasets of Tier0 test data using dq2 • Far from expected rates (FTS tuning and disk servers stability must improve) • Operation requires a lot of effort • Common procedures and instructions for Tier2’s needed chudoba@fzu.cz

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