DØ RACE DØ Internal Computing Review May 9

DØ RACE DØ Internal Computing Review May 9 – 10, 2002 Jae Yu • Introduction • Current Status • DØRAM Architecture • Regional Analysis Centers • Conclusions May 9, 2002 DØRACE DØ Internal Review, Jae Yu

How Do You Want to Do? • John Krane would say “ I want to measure inclusive jet cross section at my desk in ISU!!” • Chip Brock would say “ I want to measure W cross section at MSU!!” • Meena would say “ I want to find the Higgs at BU!!” • All of the above should be possible in the “near” future!!! • May 9, 2002 What do we need to do to accomplish the DØRACE 2 DØ Internal Review, Jae Yu above?

What is DØRACE, and Why Do We Need It? • DØ Remote Analysis Coordination Efforts • In existence to accomplish: – Setting up and maintaining remote analysis environment – Promote institutional contribution remotely – Allow remote institutions to participate in data analysis – To prepare for the future of data analysis • More efficient and faster delivery of multi-PB data • More efficient sharing processing resources • Prepare for possible massive re-processing and MC production to expedite the process May 9, 2002 Expedite physics result production DØRACE • DØ Internal Review, Jae Yu 3

DØRACE Cont’d – Maintain self-sustained support amongst the remote institutions to construct a broader bases of knowledge – Alleviate the load on expert by sharing the knowledge and allow them to concentrate on preparing for the future – Improve communication between the experiment site and the remote institutions – Minimize travel around the globe for data access – Sociological issues of HEP people at the home institutions and within the field. • Primary goal is allow individual desktop users to make significant contribution May 9, 2002 DØRACE without being DØ Internal Review, Jae Yu at the lab 4

From the Nov. Survey • Identified Difficulties – Having hard time setting up initially • Lack of updated documentation • Rather complicated set up procedure • Lack of experience No forum to share experiences – OS version differences (RH 6. 2 vs 7. 1), let alone OS – Most the established sites have easier time updating releases – Network problems affecting successful completion of large size releases (4 GB) takes a couple of hours (SA) – No specific responsible persons to ask questions – Availability of all necessary software via UPS/UPD May 9, 2002 DØRACE 5 – Time difference between continents affecting DØ Internal Review, Jae Yu

DØRACE Strategy • Categorized remote analysis system set up by the functionality – – – Phase 0 Preparation Desk top only A modest analysis server Linux installation UPS/UPD Installation and deployment External package installation via UPS/UPD Phase I Rootuple Analysis • CERNLIB • Kai-lib • Root – Download and Install a DØ release • Tar-ball for ease of initial set up? • Use of existing utilities for latest release download – – Installation of cvs Code development KAI C++ compiler SAM station setup May 9, 2002 DØRACE DØ Internal Review, Jae Yu Phase II Executables Phase III Code Dev. Phase IV Data Delivery 6

What has been accomplished? • Regular bi-weekly meetings every on-week Thursdays – Remote participating through video conferencing (ISDN) Moving toward switching over to VRVS – Keep up with the progress via site reports – Provide forum to share experience • DØRACE home page established (http: //wwwhep. uta. edu/~d 0 race) – To ease the barrier over the difficulties in initial set up – Updated and simplified instructions for set up available on the web Many institutions have participated in refining the instruction – Tools to make DØ software download and installation made available – More tools identified and are in the works (Need to automate download and installation as much as we can, if possible one May 9, 2002 7 button based operation)DØRACE DØ Internal Review, Jae Yu

• Release Ready notification system activated – Success is defined by institutions – Pull system Institutions decide whether to download and install a specific release • Build Error log and dependency tree utility in place • Release packet split to minimize network dependence • Automated one-button release download and operation utility in the works • DØRACE workshop with hands-in session in May 9, 2002 DØRACE 8 Feb. DØ Internal Review, Jae Yu

Progressive May 9, 2002 DØRACE DØ Internal Review, Jae Yu 9

Where are we? • DØRACE has entered the next stage – The compilation and running – Active code development – Propagation of setup to all institutions • Instructions seem to take their shape well • Need to maintain and to keep them up to date • Support to help problems people encounter • DØGRID – Prepare SAM and other utilities for transparent and efficient remote contribution • Need to establish Regional Analysis Centers May 9, 2002 DØRACE DØ Internal Review, Jae Yu 10

Proposed DØRAM Architecture Normal Interaction Communication Path Central Analysis Center (CAC) Regional Analysis Centers RAC Institutional Analysis IAC Centers …. Desktop Analysis Stations May 9, 2002 DAS …. IAC …. Occasional Interaction Communication Path Provide Various Services RAC IAC …. DAS DØRACE DØ Internal Review, Jae Yu DAS IAC …. DAS 11

Why do we need a DØRAM? • Total Run II data size reaches multiple PB • Data should be readily available for transparent and expeditious analyses – Preferably disk resident so that time for caching is minimized • Analysis processing compute power should be available without having the users relying on CAC • MC generation should be transparently done • Should exploit compute resources at remote sites • Should exploit human resources at remote sites May 9, 2002 DØRACE 12 DØ Internal Review, Jae Yu

What is a DØRAC? • An institute with large concentrated and available computing resources – – Many 100 s of CPUs Many 10 s of TBs of disk cache Many 100 Mbytes of network bandwidth Possibly equipped with HPSS • An institute willing to provide services to a few small institutes in the region • An institute willing to provide increased infrastructure as the data from the experiment grows • An institute willing to provide support personnel if necessary May 9, 2002 DØRACE 13 DØ Internal Review, Jae Yu

Chip’s W x-sec Measurement 3 4 2 May 9, 2002 DØRACE DØ Internal Review, Jae Yu 14

What services do we want a DØRAC do? 1. Provide intermediary code distribution 2. Generate and reconstruct MC data set 3. Accept and execute analysis batch job requests 4. Store data and deliver them upon requests 5. Participate in re-reconstruction of data 6. Provide database access 7. Provide manpower support for the above activities May 9, 2002 DØRACE DØ Internal Review, Jae Yu 15

Code Distribution Service • Current releases: 4 GB total will grow to >8 GB? • Why needed? : – Downloading 8 GB once every week is not a big load on network bandwidth – Efficiency of release update rely on Network stability – Exploit remote human resources • What is needed? – Release synchronization must be done at all RACs every time a new release become available – Potentially need large disk spaces to keep releases – UPS/UPD deployment at RACs • FNAL specific • Interaction with other systems? – Need administrative support for bookkeeping • Current DØRACE procedure works well, even for individual users Do not see the need for this May 9, 2002 DØRACE service DØ Internal Review, Jae Yu 16

Generate and Reconstruct MC data • Currently done 100% at remote sites • Why needed? – Extremely self-contained • Code distribution done via a tar-ball – Demand will grow – Exploit available compute resources • What is needed? – A mechanism to automate request processing – A Grid that can • • • Accept job requests Packages the job Identify and locate the necessary resources Assign the job to the located institution Provide status to the users Deliver or keep the results • Perhaps most undisputable task of a DØRAC May 9, 2002 DØRACE DØ Internal Review, Jae Yu 17

Batch Job Processing • Currently rely on FNAL resources – D 0 mino, Clue. D 0, CLUBS, etc • Why needed? : – Bring the compute resources closer to the user – Distribute the computing load to available resources – Allow remote users to process their jobs expeditiously – Exploit the available compute resources – Minimize resource load at CAC – Exploit remote human resources May 9, 2002 DØRACE 18 DØ Internal Review, Jae Yu

Batch Job Processing cont’d • What is needed? – Sufficient computing infrastructure to process requests • Network • CPU • Cache storage – Access to relevant databases – A Grid that can: • • • Accept job requests Packages the job Identify and locate the necessary resources Assign the job to the located institution Provide status to the users Deliver or keep the results • This task definitely needs a DØRAC – What do we do with input? Keep them at RACs? 19 DØRACE May 9, 2002 DØ Internal Review, Jae Yu

Data Caching and Delivery • Currently only at FNAL • Why needed? – Limited disk cache at FNAL • Tape access needed • Latencies involved, sometimes very long – Delivering data within a reasonable time over the network to all the requests is imprudent – Reduce resource load on the CAC – Data should be readily available to the users with minimal latency for delivery May 9, 2002 DØRACE DØ Internal Review, Jae Yu 20

• Data Caching and Delivery What is needed? cont’d – Need to know what data and how much we want to store • • 100% TMB 10 -20% DST? Any RAW data at all? What about MC? 50% of the actual data – Should be on disk to minimize data caching latency • How much disk space? (~50 TB if 100% TMB and 10% DST for Run. IIa) – Constant shipment of data to all RACs from the CAC • Constant bandwidth occupation (14 MB/sec for Run IIa RAW) • Resources from CAC needed DØRACE – A Grid that can DØ Internal Review, Jae Yu May 9, 2002 21

Data Reprocessing Services • These include: – Re-reconstruction of the actual and MC data • From DST? • From RAW? – – Re-streaming of data Re-production of TMB data sets Re-production of roottree ab initio reconstruction • Currently done only at CAC offline farm May 9, 2002 DØRACE DØ Internal Review, Jae Yu 22

Reprocessing Services cont’d • Why needed? : – The CAC offline farm will be busy with fresh data reconstruction • Only 50% of the projected capacity is used for this but … • Going to be harder to re-reconstruct as more data accumulates – We will have to • • Reconstruct a few times (>2) to improve data Re-stream TMB Re-produce TMB’s from DST and RAW Re-produce root-tree – It will take many months to re-reconstruct the large amount of data • 1. 5 Mo with 500 4 GHz machines for Run IIa • 7. 5 to 9 Mos for full reprocessing Run IIb – Exploit resources in remote institutions – Expedite re-processing for expeditious analyses • Cutting down the time by a factor of 2 to 3 will make a difference – Reduce the load on CAC offline farm May 9, 2002 DØRACE DØ Internal Review, Jae Yu 23 – Just in case the CAC offline farm is having trouble, the RACs

Reprocessing Services cont’d • What is needed? – Permanently store necessary data, because it would take a long time just to transfer data • DSTs • RAW – Large data storage – Constant data transfer from CAC to RACs as we take and reconstruct data • Dedicated file server for data distribution to RACs • Constant bandwidth occupation • Sufficient buffer storage at CAC in case network goes down • Reliable and stable network – Access to relevant databases • Calibration • Luminosity May 9, 2002 DØRACE • Geometry and Magnetic Field Map DØ Internal Review, Jae Yu 24

Reprocessing Services cont’d – Transfer of new TMB and Roottrees to other sites – Well synchronized reconstruction code – A grid that can • Identify resources on the net • Optimize resource allocation for most expeditious reproduction • Move data around if necessary – A dedicated block of time for concentrated CPU usage if disaster strikes – Questions • Do we keep copies of all data at the CAC? • Do we ship DSTs and TMBs back to CAC? • This service is perhaps the most debatable one but I strongly believe this is one of the most valuable functionality of RAC. May 9, 2002 DØRACE DØ Internal Review, Jae Yu 25

Database Access Service • Currently done only at CAC • Why needed? – For data analysis – For reconstruction of data – To exploit available resources • What is needed? – – Remote DB access software services Some copy of DB at RACs A substitute of Oracle DB at remote sites A means of synchronizing DBs • A possible solution is proxy server at the central location supplimented with a few replicated DB for backup May 9, 2002 DØRACE 26 DØ Internal Review, Jae Yu

What services do we want a DØRAC do? Ø Provide intermediary code distribution ü Generate and reconstruct MC data set ü Accept and execute analysis batch job requests ü Store data and deliver them upon requests ü Participate in re-reconstruction of data Ø Provide database access ü Provide manpower support for the above activities May 9, 2002 DØRACE 27 DØ Internal Review, Jae Yu

Progress in DØRAC Proposal • Working group members I. Bertram, R. Brock, F. Filthaut, L. Lueking, P. Mattig, M. Narain , P. Lebrun, B. Thooris , J. Yu, C. Zeitnitz • A proposal (DØ Note #3984) has been worked on – Specify the services and requirements for RAC’s – Target to release within two weeks, May 9, 2002 DØRACE sufficiently prior to the Director’s review in DØ Internal Review, Jae Yu 28

DØRAC Implementation Timescale • Implement First RAC by Oct. 1, 2002 – Cluster associated IAC’s – Transfer Thumbnail data set constantly from CAC to the RAC • Workshop on RAC in Nov. , 2002 • Implement the next set of RAC by Apr. 1, 2003 May 9, 2002 DØRACE DØ Internal Review, Jae Yu 29

Conclusions • • DØRACE has been rather successful DØ must prepare for large data set era Need to expedite analyses in timely fashion Need to distribute data set throughout the collaboration • DØRAC proposal (DØ Note # 3984) submission in two weeks • Establishing regional analysis centers will be the first step toward DØ Grid By the end of Run IIa (2 -3 years) May 9, 2002 DØRACE DØ Internal Review, Jae Yu 30