Ganga in the ATLAS Full Dress Rehearsal Birmingham 4th June 2008 Karl Harrison University of Birmingham - ATLAS Full Dress Rehearsal (FDR) involves loading simulated event sampes in bytestream format onto SubFarm disks at detector pit, and treating the data in exactly the same way as experimental data “By doing this test, we’re trying to practice everything - from data coming off the experiment all the way to shipping the data around and analysing it - under conditions just as they will be when real data-taking begins.” “[These test are] essential, almost as much as ensuring the detector itself actually works.” Dave Charlton, FDR coordinator, in ATLAS e-News (15 January 2008)

4th June 20082/4 FDR-1 and FDR-2 Full Dress Rehearsal performed in two stages  For full details see FDR Twiki page: FDR-1 - Eight runs at low luminosity (10 31 cm -2 s -1 ) played through several times during week of 4th February Reprocessing and analysis in subsequent months “Was it a success? The question is a bit like asking whether it is successful when you bring your luxury automobile to the auto mechanic and are told that, although the engine basically works, it needs a large number of parts and adjustments before it will be road worthy.” Michael Wilson, in ATLAS e-News (10 March 2008) FDR-1 - Data to be played through during week of 2nd June Analysis to follow

4th June 20083/4 UK analysis experience in FDR-1 - UK analysis experience in FDR-1 summarised in short report: - Use made of AMI (ATLAS Metadata Interface), DQ2 (data-management system) and Ganga  In general worked reasonably well -Main problems seen when using Ganga - FDR-1 datasets were small, but couldn’t analyse more than one in a single Ganga job - High probability of job failure if no destination site specified - Difficult to understand causes of job failure

4th June 20084/4 Analysis goals for FDR-2 -FDR-2 aims to allow more stringent testing of the ATLAS analysis model - Distribution with more-realistic data placement at Tier-2 sites - UK Tier-2 sites will each have 50% of the data for a single trigger stream (Muon, Egamma, MinBias, Jet) - Had 100% of data for FDR-1 - Test of ability to find data with the more-realistic placement - Analysis involving Derived Physics Data (DPD) - Had no central DPD production for FDR-1 - Tag-based analysis - Full trigger tests -Access to luminosity information  Several of these place requirements on Ganga