gridpp18 glasgow mar 07 dØ – samgrid where’ve we come from, and where are we going? evolution...

GridPP18 Glasgow Mar 07

DØ – SAMGridDØ – SAMGridWhere’ve we come from, and where Where’ve we come from, and where

are we going?are we going?

Evolution of a ‘long’ established planEvolution of a ‘long’ established plan

Gavin DaviesImperial College London


IntroductionIntroduction

• Tevatron– Running experiments (Less data than LHC, but still PBs/experiment)– Growing - great physics & better still to come..

• Have 2fb-1 of data and expect up 6fb-1 more by end 2009• 2010 running been discussed

• Computing model: Datagrid (SAM) for all data handling & originally distributed computing with evolution to automated use of common tools/solutions on the grid (SAMGrid) for all tasks– Started with production tasksStarted with production tasks eg MC generation, data processing

• Greatest need & easiest to ‘gridify’ - ahead of the wave and a running expt.

– Base on SAMGrid, but have a program of interoperability from v. early on

• Initially LCG and then OSG

– Increased automation, user analysis considered last• SAM gives remote data analysis


Computing ModelComputing Model

Remote AnalysisSystems

Data Handling Services

Central AnalysisSystems

Remote Farms Central Farms

UserDesktops

Central Storage

Raw DataRECO DataRECO MCUser Data


Components - Components - TerminologyTerminology

• SAM (Sequential Access to Metadata) – Well developed metadata & distributed data replication system– Originally developed by DØ & FNAL-CD, now used by CDF &

MINOS

• JIM (Job Information and Monitoring)– handles job submission and monitoring (all but data handling)– SAM + JIM →SAMGrid – computational grid

• Runjob – handles job workflow management

• UK Role– Project leadership– Key technology – runjob, integration of SAMGrid dev &

production


SAM plotsSAM plots

Over 10 PB (250B evts) last yrUp to 1.2 PB moved per month(x5 increase over 2 yrs ago)

•SAM TV - monitor SAM and SAM stations

• Continued success: SAM shifters – often remote

http://www-clued0.fnal.gov/%7Esam/samTV/current/

1PB / month

Allhttp://d0db-prd.fnal.gov/sam_local/SamAtAGlance/


SAMGrid-plotsSAMGrid-plots

JIM: > 10 active execution sites

“Moving to forwarding nodes”

http://samgrid.fnal.gov:8080/

http://samgrid.fnal.gov:8080/list_of_schedulers.php

http://samgrid.fnal.gov:8080/list_of_resources.php

“No longer add red dots”

http://samgrid.fnal.gov:8080/


SAMGrid SAMGrid InteroperabilityInteroperability

• Long programme of interoperability – LCG 1st and then OSG

• Step 1: Co-existence – use shared resources with SAM(Grid) headnode– Widely done for both MC and 2004/5 data reprocessing

• Nikhef MC v. good example – GridPP10 talk

• Step 2 – SAMGrid-LCG interface– SAM does data handling & JIM job submission– Basically forwarding mechanism – Data fixing in early 2006– MC since

• OSG activity – learnt from LCG activity– P20 data reprocessing now

• Replicate as needed


Monte CarloMonte Carlo

• Massive increase with spread of SAMGrid use & LCG (OSG later)

• P17 – 455M events since 09/05• 30M events/month• 80% in Eu

– Almost a const of nature

• UKRAC– Full details on web– http://www.hep.ph.ic.ac.uk/

~villeneu/d0_uk_rac/d0_uk_rac.html

• LCG gridwide submission reached scaling problem


• P14 Reprocessing: Winter 2003/04– 100M events remotely, 25M in UK– Distributed computing rather than Grid

• P17 Reprocessing: Spring – Autumn 05– x 10 larger ie 1B events, 250TB, from raw– SAMGrid as default (using mc_runjob)

• P17 Fixing: Spring 06– All RunIIa – 1.4B events in 6 weeks– SAMGrid-LCG ‘burnt-in’

• Moving to primary processing and skimming

Data – reprocessing & Data – reprocessing & fixingfixing

Site certificationSite certification


A comment..A comment..if I mayif I may

• Largest data challenges (I believe) in HEP using the grid

• Learnt a lot about the technology, and especially how it scales

• Learnt a lot about organisation / operation of such projects

• Some of these can be abstracted and of benefit to others… (a different talk…)


A comment A comment - - graphicallygraphically

• P20 reprocessing– I know its OSG– (started with LCG)

– SAMGrid-LCG• Will use to catch-up

IN2P3

OSG

A lot of green

A lot of red


(D(DØ –) RunjobØ –) Runjob

• Used in all production tasks – UK responsibility

• In 04 we froze SAM at v5 & mc_runjob used by SAMGrid for MC and reprocessing from then till summer 06

• DØrunjob - the rewrite• Joint (CDF,) CMS, DØ, FNAL-CD project• Base classes from common Runjob package

• Things got messy – but triumph– Sustainable, long term product with SAM v7

• For details see: http://projects.fnal.gov/runjob/

Runjob

CDFRunjob CMSRunjob DØRunjob


Next steps / issues - INext steps / issues - I

• Complete endgame development – ability to analysis larger datasets with decreasing manpower– Additional functionality – skimming, primary processing at

multiple sites, MC prod at diff stages, diff output…

– Additional resources - Completing the forwarding nodes• Full data /MC capability• Scaling issues to access the full LCG and OSG worlds

– Data analysis – how gridified do we go? – an open issue• My feeling – need to be ‘interoperable’

– Fermigrid, certain large LCG sites• Will need development, deployment and operations effort

– And operations..


Next steps / issues Next steps / issues - II- II

• “Steady” state – goal to reach by end of CY 07 (≥ 2yrs running)

– Maintenance of existing functionality– Continued experimental requests– Continued evolution as grid standard’s evolve

– Operations• You do still need manpower

and not just to make sure the hardware works MC and data are not fire and forget

• Manpower a real issue• (Especially with data analysis on the grid)


Summary / plansSummary / plans

• DØ and Tevatron performing very well– Big physics results have come out, better yet on their way– Much more data to come increasing needs, with reduced effort

• SAM & SAMGrid critical to DØ – Without the grid DØ would not have worked

– GridPP key part of effort (technical / leadership) – THANKS -– THANKS -– Users - demanding, hard to develop and maintain production level

services

• Baseline: Ensure (scaling for) production tasks– Move to SAMv7 and d0runjob– Accessing all LCG - establishing UKRAC – forwarding nodes

• In parallel open question of data analysis – will need to go part way

• Manpower for development, integration and operation is a real issue


Back-ups


SAMGrid ArchitectureSAMGrid Architecture

gridpp18 glasgow mar 07 dØ – samgrid where’ve we come from, and where are we going? evolution...

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