1. ATLAS: Heavier than Heaven? Roger Jones Lancaster University GridPP19 Ambleside 28 August 2007

2. RWL Jones 29 Aug. 2007 Ambleside 2 Overview Commissioning PlansCommissioning Plans Cosmics running: M3-M6 Dummy Data: T0/T1 Full Dress Rehearsals Resources in the UKResources in the UK Data DistributionData Distribution CPU, Disk, Mass Storage, Policies Operational Issues and Hot TopicsOperational Issues and Hot Topics

3. RWL Jones 29 Aug. 2007 Ambleside 3 Commissioning Plans We are now getting real data, at realistic ratesWe are now getting real data, at realistic rates M3 (mid-July) Cosmics produced about 100TB in 2 weeks Also surprised the offline by running at 4 times the nominal rate (32 samples in the LAr calorimeter ) M4 now underway - August 23 - early September Expect about Total data volume: RAW = 66 TB, ESD + AOD = 6 TB 20TB RAW data and 6TB ESD at RAL 2TB ESD at 5 Tier 2 sites Data distribution as for real data Currently writing at 200MB/sec, half nominal RAW and ESD now appearing at RAL M5 will be similar M6 will run from December until real data Will run close to nominal rate Expect ~420TB by start of run, plus Monte Carlo T1 should treat this as valuable data, but may only live for about a year

4. RWL Jones 29 Aug. 2007 Ambleside 4

5. 5 Full Dress Rehearsal First in OctoberFirst in October T0 running as per real data Data movement to Tier 1s Shipping onward to Tier 2s Some Tier 1 RAW data reprocessing and shipping of ESD, AOD to other Tier 1s This is an important step, it is a large part of operations It also prepares the group analysis activity Calibration processes These things may not all be in parallel Main FDR in FebruaryMain FDR in February Running at nominal rate More processes in parallel

6. RWL Jones 29 Aug. 2007 Ambleside 6 Resource Plan

7. RWL Jones 29 Aug. 2007 Ambleside 7 Operations We have a weekly UK Tier 1 operations meetingWe have a weekly UK Tier 1 operations meeting The attendees is a growing list For a while, we may add Tier 2 attendance as required Time will see if this requires two meetings We have more effort on the ATLAS side for operationsWe have more effort on the ATLAS side for operations The 0.5FTE at RAL from GridPP will be vital We are still seeking extra effort from ATLAS, t.b.c. ATLAS is engaged in a series of reviews with Tier 1 sitesATLAS is engaged in a series of reviews with Tier 1 sites RAL was ‘done’ on July Constructive discussion, problems faced openly Very useful ‘live’ document of data classes/disk servers/tape servers/ endpoints continuing to evolve

8. RWL Jones 29 Aug. 2007 Ambleside 8 ATLAS T0-T1 Exports Mon/Tuesday 28/29 May 2007 Mbytes/second Despite RAL problems, ATLAS was having some success RAL is now in, and showing good rates

9. RWL Jones 29 Aug. 2007 Ambleside 9 Data Storage The disk problems + Castor problems have meant that RAL was effectively ‘off’ for half a yearThe disk problems + Castor problems have meant that RAL was effectively ‘off’ for half a year This has a knock-on effect Data was not flowing properly to the Tier 2s This means the analysis usage at the Tier 2s is severly restricted Ad hoc work around for the Tier 2s were only partially effective This will take a long time to work out of the system Disk only storage now going to dCacheDisk only storage now going to dCache This means that we will have a large migration issue and may need extra disk for a period Castor 2.1.3 seems a big improvement, we hope for a quick and stable 2.1.4Castor 2.1.3 seems a big improvement, we hope for a quick and stable 2.1.4 Good interactions with the Tier 1 team More generally, we still need to be able to apply quotas based on VOMS roles etcMore generally, we still need to be able to apply quotas based on VOMS roles etc

10. RWL Jones 29 Aug. 2007 Ambleside 10 Data Placement The data movement and placement system is Don Quijote 2 (DQ2)The data movement and placement system is Don Quijote 2 (DQ2) A new major version was rolled-out in the late spring More robust transfers Rate throttling etc The effectiveness depends on the tools folded with the policyThe effectiveness depends on the tools folded with the policy ATLAS works with datasets Subscriptions only become active when a dataset is complete We were letting datasets stay open to grow - fixed Only transfer to Tier 2 when the Tier 1 has the full dataset This is not fixed - many sets from BNL, who have low effective outwards bandwidth

11. RWL Jones 29 Aug. 2007 Ambleside 11 Advice for Tier 3s Working definition: ‘Tier 3’ facilities are for local use, not for all of ATLASWorking definition: ‘Tier 3’ facilities are for local use, not for all of ATLAS Need a Grid interface There are some common requirements ATLAS Tier 3 task force is starting to give recommendations and to describe possible solutionsATLAS Tier 3 task force is starting to give recommendations and to describe possible solutions Aim is to help sites This will be advisory, not prescriptive! They can come in different forms, many ideasThey can come in different forms, many ideas Dedicated cpu and disk racks Fraction of fabric for Tier 2s Desktop clusters

12. RWL Jones 29 Aug. 2007 Ambleside 12 ATLAS Requirements start 2008, 2010 CPU (MSi2k) Disk (PB) Tape (PB) 200820102008201020082010 Tier-03.76.10.150.52.411.4 CERN Analysis Facility 2.14.61.02.80.41.0 Sum of Tier-1s 18.15010407.728.7 Sum of Tier-2s 17.551.57.722.1 Total41.4112.218.965.410.541.1 Note the high ratio of disk to cpu in the Tier 2s Not yet realised May require adjustments

13. RWL Jones 29 Aug. 2007 Ambleside 13 Summary ATLAS is now doing exercises with real data at realistic ratesATLAS is now doing exercises with real data at realistic rates After a very bad 6 months, the UK is now in ATLAS exercises and looking quite goodAfter a very bad 6 months, the UK is now in ATLAS exercises and looking quite good Good relations with T1 Still concern over the storage solutions Migration from dCache will be painful and take extra resources The FDRs are important tests and we have to make them workThe FDRs are important tests and we have to make them work We have used the Tier 2s surprisingly well considering the problems with the data flowWe have used the Tier 2s surprisingly well considering the problems with the data flow The next year will be ‘interesting’ (but rewarding)The next year will be ‘interesting’ (but rewarding)