Summary of Services for the MC Production

Patricia Méndez LorenzoWLCG T2 Workshop

CERN, 12th June 2006

Patricia Méndez Lorenzo WLCG T2 Workshop 12 th June 2006

Outline

Main Purpose Present the T2 infrastructure required by each experiment

at the sites

Content of the talk Summary of the T2 activities experiment by experiment T1-T2 association

Each experiment has provided different information Not following therefore a similar structure for each

experiment during this talk

It tries to be a initial “draft” to be completed after the session

Patricia Méndez Lorenzo WLCG T2 Workshop 12 th June 2006 3

ALICE: Generalities Distribution of tasks per Tiers in the ALICE

computing modelT2 is responsible for MC simulation and analysisDifference between T1 and T2 for ALICE is only QoS

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ALICE: MC Production on T2`s

Production extensively tested in 2 data challenges: PDC’05 and the ongoing PDC’06

Standard setup – LCG/gLite with an ALICE VOBOX (as on the T1s)Distributed at all T1`s and T2`sAt WMS level they are at the same level

All job submission to T2s is through the Grid:Installation of application software, including simulation

packages is handled through the ALICE Grid toolsProduced MC data are stored on the local SE and

transferred for safekeeping to the host T1

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ALICE: Specific T2 Requirements

Large amount of memory consumption per job: 2 GB max

Job duration - typically 8 KSI2k hours Input Data - minimal set of configuration Output Data - up to 1.5 GB/job, standard 300

MB The jobs are (naturally) CPU-intensive, no

stringent requirement on storage

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ALICE: PDC`06 tests of T2

Generally, ALICE is doing tests of all elements of the computing model

The MC production - ongoing In July 2006, T2-T1 transfers (FTS) tests

Relational matrix T2-host T1 is being built Installation of FTS client infrastructure is

ongoing

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ALICE: T1-T2 relations

In the ALICE computing model there are not privileged relations among T1`s and T2`s Both types of sites hold VOBOXES Both types of sites hold local LFC

Relations T1-T2 are based in terms of storage and transfers MC data and AOD from analysis at T2 shipped to the

closest T1 for custodial purposes

In countries with a T1, T2`s are the country to refer France, Germany and Italy

In countries with no T1, this role should be played by the site with the best bandwidth

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ATLAS: Generalities

Main Activities to perform in the T2`s Run the data simulation Hold AOD (in disk for analysis) generated at T0

and distributed among T1 and T2 Run the user analysis jobs

ATLAS consider a hierarchical structure between T1`s and T2`s Defined by the generation and distribution of data Associated to the baseline services required for

their production

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ATLAS: Distribution of Data

RAW data (T0)T1: Part of raw data, fraction of ESD and full set of AOD

Nominal AOD data rate: 20MB/s

T2: Receive also AOD from T1`sLarge T2`s storing full sets of AOD`sSmall T2`s sharing full sets

Reprocessing of raw data (T1)Production of ESD to exchange between T1`sAOD to distribute to other T1`s and T2`sExpected a 20MB/s to T2`s

Simulation (T2)Data transferred to T1`s for ist permanent storageLow upload from T2 to T1 (few MB/s)

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ATLAS: Baseline Services

Baseline Services to build the ATLAS infrastructureFTS and LFC

The ATLAS DDM uses these blocks to define a hierarchical and distributed data cataloging Central dataset catalogues: Information of datasets and

locationLocal File catalogues: Mapping PFN vs LFN

FTS and LFC managed by T1`sEach T1 provides services to a certain group of T2`s

Defining regions consisting in each T1 and associated T2`s

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ATLAS: Definition of regions

Each T1 will group a certain set of T2`s where to download AODs and upload simulated dataFast and reliable network required

T1 holds the local LFC`s and contains the entries of those files storaged in the T2`sFast communication between running jobs at T2 and local

catalogue at T1Geographically closed

Matching of CPU capability of the T2 and Storage power of the T1Large countries will provide matching capacities between T1

and T2Small countries will provide either T1 or T2

Handling the problemsFast human connections (not 12 hours of difference)

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List of Services required at T2 during SC4

Not particular requirements besides a SRM based SEGeneral services provided by the Grid

infrastructure, CE, SE...

FTS to be set at T1`sNominal rate to T2: 20MB/s during 24 hExpertise in SE installation and maintenance

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CMS: Simulation Production at T2

Simulation ProductionGeneration Phase

Small input configuration file, large output datasetHigh CPU activity

Simulation, reconstructionNew iterationsSet of input data and production of output data

More similar to analysisI/O activities included

Simulation at T2Produced data defined by the physics groupsIndividual user productions also foreseen

Transparent for the T2

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CMS: Simulation ProcedureWorkflow

Jobs submitted centrally using a set of automatic toolsCentral request queue: Production ManagerManagement of jobs by the Production Agents

Human support for possible failures is needed

DataflowSimulated data stored at T1

Backup on tapeReprocessing and distribution to other T2 maybe

neededT2 WNs stored the output locally

For validation purposesMarge of files locally (I/O operations)

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CMS: Requirements

T2 will provide disk and CPU to perform the simulation and the majority of the analysis

CMS requires:Good behavior: Pass all SFTGood and solid batch farmGood storage: size, performance and servicesSRM accessFTS channels

The server is placed at T1 but the good transfer is the responsibility of the two ends

Good I/OGood network

1Gbit/s for data movementFast local access for read/write

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CMS:Services

CMS ServicesCMS software distributionIntegration of LFC and PhEDEx (on top of FTS) in

the Data Management system

Tasks of the T2`sThe good behavior of the site is its tasks

Good management of the jobs and fixing the SW area cannot be done by the experiment

Active and responsible T2 is wishedGood communication with the experiment is

fundamental

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LHCb: Generalities

T0Generation of raw data, reconstruction, stripping

and user analysisT1

Besides real data taking, similar tasks as T0T2

Monte Carlo production (no analysis phase)At least in countries also providing T1

T2 are considered PC-farms with a small disk buffer Disk used as temporary cache until data are transferred

to T1 Full copy also at CERN

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LHCb: Analysis at T1

The LHCb analysis jobs consist in selecting the events stored at T1 and focus on a particular channel of analysisTypical analysis jobs run on a 106 event sampleSome analysis jobs will run even larger event

samples (107)The analysis input is completely stored at each T1The output can be processed in smaller sites

To perform the analysis at the T1 seems to be faster and less expensive in terms of hardware, infrastructure and staff resources than running it at T2`s

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LHCb: T2 Requirements

In terms of softwareWell known functionality since they only perform

MC productionCE, SE, RB, GPBOX (policy enforcement mechanism)

T2 are not technically critical in LHCbThey only have to produce the required amount of MC

data

In terms of supportFundamental a good performance of the T1

Need of dedicated personnel cannot be set asideInfrastructural and organizational problems must be

solved

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T1-T2 Association

During the Rome GDB it was asked to the experiments to provide the T2-T1 relationships Here we have the (in some cases) tentative table It is still an open question for some sites and an

issue to be solved

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ALICE CCIN2P3

French T2, Sejong (Korea), Lyon T2, Madrid (Spain) CERN

Capa Town (South Africa), Kolkata (India), T2 Federation (Romania), RMKI (Hungary), Athens (Greece), Slovakia, T2 Federation (Poland), Wuhan (China)

FZK FZU (Czech Republic), RDIG (Russia), GSI and Muenster

(Germany) CNAF

Tier2 Federation RAL

Birmingham SARA/NIKHEF PDSF

Houston

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ATLAS

BNL USA T2 Federation

TRIUMF Canada T2 Federation

NDGF Ljubljana

PIC Spanish T2 Federation Portuguese Federation

RAL T2 in UK

CNAF T2 in Italy

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ATLAS (cont.)

CCIN2P3 T2 in France Romanian Federation Alternative data path for Beijing Alternative data path for Tokyo

ASGC Melbourne Beijing Tokyo

NIKHEF Russian Federation Israeli Federation Alternative path for NorthGrid and Prague

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CMS

CCIN2P3 Belgium T2 France

FZK German T2 Poland Russia Switzerland

CNAF Greece Hungary Italian T2

PIC Portugal T2 Spain T2

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CMS (cont.)

ASCC India Korea Pakistan Taiwan

RAL Estonia T2 UK

FNAL Brazil US

China, Croatia, Finland to be confirmed

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LHCb T2 mapped to CERN and T1 CNAF

Italian T2 RAL

UK T2 PIC

Spain T2 FZK

German T2 Poland Switzerland

CERN Russia

CCIN2P3 France T2, Bulgaria + west of meridian line

NIKHEF Nederlands + east of meridian line

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Summary

All the experiments will run the MC production in the T2Apart of LHCb, all of them will also run the analysis

CMS foreseen an important I/O activity

Data will always be transferred to T1 for storingAll experiments are requiring good catalogues and

transfers servicesALICE puts in this sense the T2 performance to the T1 levelATLAS defines a more hierarchical structure

The responsibility of the corresponding T1 is fundamentalThe association T1-T2 should be clarify as soon as

possible on those countries with no T1