Massive Computing at CERN and lessons learnt

Bob JonesCERN

Bob.Jones <at> CERN.ch

• A distributed computing infrastructure to provide the production and analysis environments for the LHC experiments

• Managed and operated by a worldwide collaboration between the experiments and the participating computer centres

• The resources are distributed – for funding and sociological reasons

• Our task is to make use of the resources available to us – no matter where they are located

Ian Bird, CERN 2

WLCG – what and why?

What is WLCG today?

Ian.Bird@cern.ch 3

Service coordinationService coordinationService managementService management Operational securityOperational security

World-wide trust federationfor CA’s and VO’s

World-wide trust federationfor CA’s and VO’s

Complete Policy frameworkComplete Policy framework

FrameworkFramework

Support processes & toolsSupport processes & tools Common toolsCommon tools Monitoring & AccountingMonitoring & Accounting

CollaborationCollaborationCoordination & management & reportingCoordination & management & reporting

Common requirementsCommon requirements

Coordinate resources & fundingCoordinate resources & funding

Memorandum of Understanding

Coordination with service & technology providersCoordination with service & technology providers

Physical resources: CPU, Disk, Tape, NetworksPhysical resources: CPU, Disk, Tape, Networks

Distributed Computing servicesDistributed Computing services

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WLCG data processing model

Tier-1 (11 centres):•Permanent storage•Re-processing•Analysis

Tier-0 (CERN):•Data recording•Initial data reconstruction•Data distribution

Tier-2 (~130 centres):• Simulation• End-user analysis

Lyon/CCIN2P3Barcelona/PIC

De-FZK

US-FNAL

Ca-TRIUMF

NDGF

CERNUS-BNL

UK-RAL

Taipei/ASGC

Ian Bird, CERN 526 June 2009

Today we have 49 MoU signatories, representing 34 countries:

Australia, Austria, Belgium, Brazil, Canada, China, Czech Rep, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, India, Israel, Japan, Rep. Korea, Netherlands, Norway, Pakistan, Poland, Portugal, Romania, Russia, Slovenia, Spain, Sweden, Switzerland, Taipei, Turkey, UK, Ukraine, USA.

Today we have 49 MoU signatories, representing 34 countries:

Australia, Austria, Belgium, Brazil, Canada, China, Czech Rep, Denmark, Estonia, Finland, France, Germany, Hungary, Italy, India, Israel, Japan, Rep. Korea, Netherlands, Norway, Pakistan, Poland, Portugal, Romania, Russia, Slovenia, Spain, Sweden, Switzerland, Taipei, Turkey, UK, Ukraine, USA.

WLCG Collaboration StatusTier 0; 11 Tier 1s; 64 Tier 2 federationsWLCG Collaboration StatusTier 0; 11 Tier 1s; 64 Tier 2 federations

Amsterdam/NIKHEF-SARA

Bologna/CNAF

Ian Bird, CERN 6

Fibre cut during 2009:Redundancy meant no interruption

Worldwide resources

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• >140 sites• ~250k CPU cores• ~100 PB disk

• >140 sites• ~250k CPU cores• ~100 PB disk

• MoU defines key performance and support metrics for Tier 1 and Tier 2 sites– Reliabilities are an approximation for some of these– Also metrics on response times, resources, etc.

• The MoU has been an important tool in bringing services to an acceptable level

Ian Bird, CERN 8

Service quality: defined in MoU

Ian Bird, CERN 9

From testing to data:Independent Experiment Data ChallengesIndependent Experiment Data Challenges

Service Challenges proposed in 2004To demonstrate service aspects:

-Data transfers for weeks on end-Data management-Scaling of job workloads-Security incidents (“fire drills”)-Interoperability-Support processes

Service Challenges proposed in 2004To demonstrate service aspects:

-Data transfers for weeks on end-Data management-Scaling of job workloads-Security incidents (“fire drills”)-Interoperability-Support processes

2004

2005

2006

2007

2008

2009

2010

SC1 Basic transfer ratesSC1 Basic transfer rates

SC2 Basic transfer ratesSC2 Basic transfer rates

SC3 Sustained rates, data management, service reliabilitySC3 Sustained rates, data management, service reliability

SC4 Nominal LHC rates, disk tape tests, all Tier 1s, some Tier 2sSC4 Nominal LHC rates, disk tape tests, all Tier 1s, some Tier 2s

CCRC’08 Readiness challenge, all experiments, ~full computing models

CCRC’08 Readiness challenge, all experiments, ~full computing models

STEP’09 Scale challenge, all experiments, full computing models, tape recall + analysis

STEP’09 Scale challenge, all experiments, full computing models, tape recall + analysis

• Focus on real and continuous production use of the service over several years (simulations since 2003, cosmic ray data, etc.)• Data and Service challenges to exercise all aspects of the service – not just for data transfers, but workloads, support structures etc.

e.g. DC04 (ALICE, CMS, LHCb)/DC2 (ATLAS) in 2004 saw first full chain of computing models on grids

e.g. DC04 (ALICE, CMS, LHCb)/DC2 (ATLAS) in 2004 saw first full chain of computing models on grids

• LHC, the experiments, & computing have taken ~20 years to build and commission

• They will run for at least 20 years• We must be able to rely on long term

infrastructures– Global networking– Strong and stable NGIs (or their evolution)

• That should be eventually self-sustaining

– Long term sustainability - must come out of the current short term project funding cycles

Ian Bird, CERN 10

Large scale = long times

• CERN and the HEP community have been involved with grids from the beginning

• Recognised as a key technology for implementing the LHC computing model

• HEP work with EC-funded EDG/EGEE in Europe, iVDGL/Grid3/OSG etc. in US has been of clear mutual benefit– Infrastructure development driven by HEP needs– Robustness needed by

WLCG is benefitting other communities

– Transfer of technology fromHEP

• Ganga, AMGA, etc used by many communities now

Ian Bird, CERN 11

Grids & HEP: Common history

www.egi.euEGI-InSPIRE RI-261323 www.egi.euEGI-InSPIRE RI-261323

European Grid Infrastructure

• European Data Grid (EDG)– Explore concepts in a testbed

• Enabling Grid for E-sciencE (EGEE)– Moving from prototype to production

• European Grid Infrastructure (EGI)– Routine usage of a sustainable e-

infrastructure

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www.egi.euEGI-InSPIRE RI-261323

European Grid Infrastructure(Status April 2011 – yearly increase)

• 13319 end-users (+9%)• 186 VOs (+6%)• ~30 active VOs: constant• Logical CPUs (cores)

– 207,200 EGI (+8%)– 308,500 All

• 90 MPI sites• 101 PB disk• 80 PB tape• 25.7 million jobs/month

– 933,000 jobs/day (+91%)• 320 sites (1.4%)• 58 countries (+11.5%)

EGI - The First Year 13

ArcheologyAstronomyAstrophysicsCivil ProtectionComp. ChemistryEarth SciencesFinanceFusionGeophysicsHigh Energy PhysicsLife SciencesMultimediaMaterial Sciences…

Non-HEP users ~ 3.3M jobs / month

Grids, clouds, supercomputers, etc.

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Grids• Collaborative environment• Distributed resources (political/sociological)• Commodity hardware• (HEP) data management• Complex interfaces (bug not feature)• Communities expected to contribute resources

Supercomputers• Scarce• Low latency interconnects• Applications peer reviewed• Parallel/coupled applications• Also SC grids (DEISA/PRACE, Teragrid/XD)

Clouds• Proprietary (implementation)• Economies of scale in management• Commodity hardware• Pay-as-you-go usage model• Details of physical resources hidden• Simple interfaces

Volunteer computing• Simple mechanism to access millions CPUs• Difficult if (much) data involved• Control of environment check • Community building – people involved in Science• Potential for huge amounts of real work

CERN IT Department

CH-1211 Genève 23

Switzerlandwww.cern.ch/it

• Philosophy: promote web-based citizen participation in science projects as an appropriate low cost technology for scientists in the developing world.

• Partners: CERN, UN Institute for Training and Research, University of Geneva • Sponsors: IBM, HP Labs, Shuttleworth Foundation • Technology: open source platforms for internet-based distributed collaboration• Projects:

– Computing for Clean Water optimizing nanotube based water filters by large scale simulation on volunteer PCs

– AfricaMap volunteer thinking to generate maps of regions of Africa from satellite images, with UNOSAT

– LHC@home new volunteer project for public participation in LHC collision simulations, using VM technology

• Plans: Training workshops in 2011 in India, China, Brazil and South Africa

Collaboration with the General Public:Citizen Cyberscience Centre

Frédéric Hemmer 15

Some more questions to be answered• Computing model

– How many computing models exist in the community and can they all use the same computing infrastructure?

• Continuous load or periodic campaigns?– How intensely and frequently will the community use the computing

infrastructure?

• Manpower– Do you have enough geeks to port the code and support it?

• How committed is the community?– Are you prepared to contribute and share computing resources?

Bob Jones – May 2011 16