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

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

3. chudoba@fzu.cz 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

4. chudoba@fzu.cz 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

5. chudoba@fzu.cz 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

6. chudoba@fzu.cz 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)

7. chudoba@fzu.cz 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

8. chudoba@fzu.cz 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