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Planning Resources for LHCb Computing Infrastructure. John Harvey LHCb Software Week July 5-7 2000. Outline. Basic questions on LHCb Computing Model Technical requirements Plan for tests and the 2003 Prototype Milestones Costing and mapower Guidelines for MoU
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Planning Resources for LHCb Computing Infrastructure John Harvey LHCb Software Week July 5-7 2000
Outline • Basic questions on LHCb Computing Model • Technical requirements • Plan for tests and the 2003 Prototype • Milestones • Costing and mapower • Guidelines for MoU • Calendar of summer activities • Summary
Simulation production Analysis Central data store Data recording, calibration Reconstruction, reprocesssing Central data store Selected user analyses Local data store CERN Tier 0 Tier 1 UK Tier 1 France Tier 1 Italy AOD,TAG real : 80TB/yr sim: 120TB/yr CERN Tier 1 Oxford Roma I Barcelona Marseilles AOD,TAG 8-12 TB/yr Computing Model Tier 1 Spain ? ? ?
Some basic questions • Which are the LHCb Tier 1 centres? • UK, France, Italy, ……? • We are being asked this question now. • How will countries without a Tier 1 centre access LHCb datasets and do analysis? • For each centre we need to ascertain whether there is a policy for permitting remote access to resources e.g. is it: • A collaboration-wide resource? • Restricted by nationality? • How will use of resources be allocated and costed?
Technical Requirements • Tier 0 - real data production and user analysis at CERN • 120,000 SI95 cpu, 500 TB/yr, 400TB (export), 120 TB(import) • Tier 1 – simulation production and user analysis • 500,000 SI95 cpu, 330TB/yr, 400 TB (export), 120TB (import) • Shared between Tier 1 centres • Requirements need to be revised • New estimates of simulation events needed – evolution with time • Number of physicists doing analysis at each centre • Comparison with estimates from other experiments to look for discrepancies (e.g. analysis) • Sharing between Tier 0 and Tier 1 needs to be checked • 1/3 (CERN) 2/3 (outside) guideline
Tests and the 2003 Prototype • Adaptation of LHCb production software to use grid middleware (i.e. Globus) has started • Production tests of new data processing software – performance and quality • Production tests of the computing infrastructure • Performance of hardware, scalability • Tests of the grid infrastructure • Construction of a large scale prototype facility at CERN • Adequate complexity (no of physical cpus, switches, disks etc.) • Suitable architecture – scope covers on- and off-line • Tests – scalability under different workloads, farm controls, data recording • Shared participation and exploitation by all 4 experiments • Planned for 2003 – sufficient time to get experience • Scale limited by ATLAS/CMS needs
CERN Tier 0 Tier 1 UK Tier 1 Italy x2 Tier 1 France Tier 1 USA x2 CERN Tier 1 2003 Prototype Tier 1 others ? • CERN Tier 0 shared by all 4 expts even in 2005 – large! • Which are the Tier 1 centres that will participate in prototype? • Tier 1s decide how big they will be in prototype
Computing Milestones • 2H2001 – Computing MoU • assignment of responsibilities (cost and manpower) • 1H2002 –Data Challenge 1 (Functionality test) • Test software framework machinery (database etc.) • Test basic grid infrastructure (>2 Tier 1 centres) • Scale of test ~ 106 events in ~1 month – modest capacity • 2H2002 – Computing TDR • 1H2003 – Data Challenge 2 (Stress tests using prototype) • Stress tests of data processing ~107 events in 1 month • Production (simulation) and chaotic (analysis) • Repeat tests of grid with all Tier 1 centres if possible • Include tests designed to gain experience with the online farm environment – data recording, controls
Planning • Need to establish participation of Tier 1 centres • In grid tests • In 2003 prototype tests • Coordination between Tier 1s and experiments (EU project etc.) • Plan Data Challenges • Tasks, manpower schedule and milestones • Define technical details • Match to physics milestones – ongoing simulation work • Plan resources needed at each centre between now and 2005 • To participate in tests • To participate in simulation production
Costing and Manpower • We need to identify our requirements at each centre and work with their local experts to cost our needs. • The centre should apply its own specific costing model to make estimates of the resources required to service LHCb needs as a function of time. This includes : • Unit costs of cpu, managed storage, network bandwidth, … • On-going maintenance costs • Policy for replacement and upgrade • The staffing levels in the Tier0 and Tier1s required for LHCb should be addressed jointly by LHCb and the centres’ experts to determine : • Dedicated LHCb support staff • Cost of services - breakdown as in-house and outsource • We can then compare these figures with our own estimates of the cost – ultimately we have responsibility for ensuring that the LHCb computing cost estimate is correct. • We need to estimate the evolution in the cost from now to 2005 i.e. including the cost of the prototype
Guidelines to write the Computing MOU • Assignment of responsibility (cost and manpower) for the computing infrastructure • Provision of computing resources • Breakdown by centres providing production capacity • Remote access policies of Tier 1 centres • Maintenance and operation costs • Manpower for computing centres • Part of centre strategic planning i.e. not for LHCb MoU • Manpower for CORE computing components • CORE software components – institutional agreements • Software production tasks – librarian, quality, planning, doc,.. • Data production tasks – operation, bookkeeping • Manpower for detector specific computing • Follows institutional responsibility for detector • Timescale – write during 2001, sign when ready
Construction of prototype • We need to understand how the construction of the prototype will be funded and how costs will be shared • This need not necessarily require an MoU if an informal agreement can be reached • We are expected to describe how we intend to use the prototype and to make a commitment on the manpower that will be used to provide the applications and to perform the tests.
The calendar for the summer activities • 17th July – Review Panel 3 • Location of Tier 1 centres • LHCb technical requirements - to be sent to centres for costing • Participation of Tier 1 centres in prototype • 22nd August – Review Panel 3 • 20th September – Review Panel 3 • 25-29 September – LHCb collaboration meeting • October 3 – Review Steering – report almost final • October 9 – Review Panel3 • October 10th – finalise review report and distribute • October 24th – RRB meeting – discussion of report
Summary • We need to refine model : • Where are theTier 1s? • How will physicists at each institute access data and do analysis? • We need to revise technical requirements • New estimates of simulation needs • Checks against requirements of other experiments • We need to define tests, MDCs and use of 2003 prototype • We need to make cost and manpower estimates • Working with the various centres • Next year we will need to write a Computing MoU defining the assignment of responsibility for costs and manpower • Will be signed only when all details are fixed