Tuesday, 10 June 2008

May Data Transfers from CERN: CMS @ CCRC'08

During CCRC'08 May tests CMS tested the reliability and robustness of Data Transfers from CERN to all Tier-1 centers. The main metric was to be able to export data from CERN above nominal rate (600MB/sec) for more than 3 days. The individual metric was satisfied at all Tier-1 centers, except for FZK and FNAL.

For PIC, the importing shared target rated was of about 57 MB/s. PIC was all days over the metric, with some days importing a factor x2 than requested.

It is important that data flows from CERN in a smooth way. From reliability and robustness p.o.v. being 3-4 days over the metric is really bad for data taking as we could be stuck at the CERN overrunning CMS buffers. PIC was always over the metric during the whole month and a comparison to other Tier-1s can be seen on this table.

Last, but not least, the mean May '08 rate CERN->PIC was of 70 MB/s, with an impressive Data Transfer Quality of 90%. The test was successful and quite impressive for PIC indeed!

Tuesday, 3 June 2008

A picture is worth a thousand words...

During the run2 of the CCRC08 (Common Computing Readiness Challenge), ATLAS tested the full chain of Distributed Computing Activities as if the detector was working: CERN=>T1s data exportation, T1 cross-transfers, T1s=>T2s data replication, Data Reprocessing and Simulated events production. The overall exercise was a success, in spite of small failures and outages that weren't strong enough to spoilt the tests. We tested the full chain and push the distribution over the limits (200% nominal rates) , now we are more confident while waiting for the protons to collide -end of August !-

PIC demonstrated it's reliability during the whole month achieving an efficiency of 91% (Best Tier-1) acquiring data, the high demanding reprocessing jobs push the Worker Nodes and pools to the limit and was very useful to the collaboration. Also the Tier-2s received data without major problems, I want to mention all PIC team that made possible such a good performance in every single activity. And as I mentioned in the title... A picture is worth a thousand words: