Grid activities at the ALICE Experiment
Roberto Barbera
On behalf of the ALICE GRID Working Group:
G. Andronico (CT), T. Anticic (IRB), R. Barbera (CT),
I.J.Bloodworth (Birmingham), M. Botje (NIKHEF), P. Buncic
(CERN), F. Carminati (CERN), P. Cerello (TO), G. Chabratova
(DUBNA), J. Cleymans (South Africa), J. G. Contreras
(MERIDA), D. Di Bari (BA), D. De Girolamo (BA), J. Gosset
(SACLAY), A. Grigoryan (Yerevan), M.L. Luvisetto (BO), P.
Malzacher (GSI), M. Masera (CERN/TO), A. Masoni (CA), K.
Mkoyan (Yerevan), D. Mura (CA), L. Nellen (UNAM), B.
Nilsen (OSU), S.K. Pal (Calcutta), F. Pierella(BO), F.
Rademakers (CERN), Y. Schutz (SUBATECH), E. Scomparin
(TO), M. Sitta (TO), R. Turrisi (PD), D. Vicinanza (SA) 1
TNC2002, 03-06.06.2002
CHEP 2000, 10.02.2000
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Outline
The ALICE Experiment
Grid activities at ALICE:
the past: tests with Globus
 the present: AliEn, PROOF and DataGrid tests
 the future: grid interoperability with AliEn

Summary and conclusions
TNC2002, 03-06.06.2002
2
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
The Large Hadron Collider
http://www.cern.ch
LHC
~9 km
SPS
CERN
TNC2002, 03-06.06.2002
3
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
The 4 LHC Experiments
TNC2002, 03-06.06.2002
4
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
The ALICE Detector
TNC2002, 03-06.06.2002
5
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
TNC2002, 03-06.06.2002
The Little Bang
The Big Bang
The Quark Gluon Plasma
Pb+Pb @ LHC (5.5 A TeV)
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
1/100 of a Pb+Pb @ LHC !
Simulation and reconstruction of a “full” (central) Pb+Pb collision
at LHC (about 84000 primary tracks!) takes about 24 hours of a
top-PC and produces an output bigger than 2 GB.
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
ALICE data per year
2-3 Petabytes !
˜4.000.000 CD-ROM
TNC2002, 03-06.06.2002
2+ times the
Eiffel Tower
600+ m
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
ALICE “computing” sites today
OSU/OSC
LBL/NERSC
Birmingham
Nantes
Dubna
NIKHEF
Saclay
GSI
CERN
Merida
Lyon
Torino
Padova
Bologna
IRB
Bari
~O(108) events/year
~O(103) batch and interactive users
in 2006
Cagliari
Yerevan
Catania
Kolkata, India
Capetown, ZA
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Computing model
Online System
Online Farm
~1.25 GB/s
622/2500 Mb/s
Tier 1
France Regional
Center
Tier 0
Germany Regional
Center
Italy Regional
Center
CERN Computer
Center
UK Regional
Center
2.5/10 Gb/s
Tier 2
Tier2 Center Tier2 Center
Tier2 Center
Tier2 Center
Tier2 Center
155/622 Mb/s
Tier 3
Institute Institute InstituteInstitute
Physics data cache
100 - 1000
Mb/s
Tier 4
TNC2002, 03-06.06.2002
Monarc Project
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
I’m the PPR
production manager
ALICE Collaboration
Disk
Linux farm +
MRTG monitor
EnginFrame
Manager’s site
I’m the local
site manager
Install/Update
PHP
Bypass
DB
bbFTP
Tape Pool
(CASTOR/
HPSS)
WWW/
Carrot
I’m the impatient
ALICE user checking the
availability of events
Production site
Lay-out 2000/’01
TNC2002, 03-06.06.2002
Cron Mirror
MySQL
Globus
AliEn
Reposit.
Run
DB
Pool
WWW/Carrot
Anywhere
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
Web interface to login
on “The Grid”
TNC2002, 03-06.06.2002
Utilities
Network
CPU
DiskLoad
space
availability
Only at Lyon
Book keeping system
ALICE Collaboration
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
AliEn: the ALICE grid prototype
TNC2002, 03-06.06.2002
13
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
AliEn architecture
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
AliEn authentication
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
First production with AliEn
PPR PB-PB + P-P PROD.
sito
# Job
CERN
LYON
OSC
LBL
NIKHEF
TORINO
CATANIA
PADOVA
BARI
CPU norm.
2508
115280146
PPR
p-p AND Pb-Pb
production (JOBS)
726
71583048
44 0%
2511390
CERN
PPR p-p and
0% Pb-Pb production (CPU)
11%
807
26679717
0%
LYON
1%
30
2942802
OSC
6%
1141
25337047
19%
LBL
42%
623 10% 15853058
NIKHEF
12 1%
2858924
TORINO
1%
2 10%
398664 44%
CATANIA
14%
PADOVA
5893
263444796
1%
1%
12%
27%
TNC2002, 03-06.06.2002
BARI
CERN
LYON
OSC
LBL
NIKHEF
TORINO
CATANIA
PADOVA
BARI
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
PROOF: Parallel ROOt Facility
Selection
Parameters
TagD
B
CPU
Procedure
PROOF
RD
B
Proc.C
Proc.C
Proc.C
Proc.C
Proc.C
TNC2002, 03-06.06.2002
DB
1
DB
2
DB
3
DB
4
DB
5
DB
6
CPU
Local
Remote
CPU
CPU
CPU
CPU
17 Barbera
Roberto
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Experiences with DataGrid
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Experiences with DataGrid
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Experiences with DataGrid
TNC2002, 03-06.06.2002
20
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Experiences with DataGrid
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Automatic check of the Testbed
TNC2002, 03-06.06.2002
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
The future: AliEn as a meta-grid
AliEn User Interface
iVDGL stack
TNC2002, 03-06.06.2002
AliEn stack
EDG stack
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Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Interfacing the Grid(s) - I
Job submission/control/monitoring:
Application: AliRoot
Data Persistency: Root
AliEn
Data Catalogue: AliEn
Job parallelisation:
Root/PROOF
ROOT
AliRoot
AliEn API/PROOF
IVDGL
EDG/EDT
AliEn Services (shell, web)
TNC2002, 03-06.06.2002
By P.Cerello
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Interfacing the Grid(s) - II
AliEn Job
MetaData
Catalogue
EDG RB
AliEn Job
AliEn Job
EDG CE
Alice
Farm
AliEn Job
AliEn Job
AliEn Job
EDG
WN
I-LFN
Condor-G
AliEn Job
O-PFN
AliEn Job
EDG SE
AliEn Data
Catalogue
Alice
User
TNC2002, 03-06.06.2002
O-LFN,O-PFN
I-PFN
By P.Cerello
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Interfacing the Grid(s) - III
I-LFN(s)
MetaData
Catalogue
I-LFN(s)
AliEn Data
Catalogue
I-PFN(s)
EDG
WN
I-PFN3
I-PFN2
PROOF
I-PFN1
EDG
SE1
EDG
CE2
EDG
CE3
EDG
SE2
EDG
SE3
O-PFN3
O-PFN1
TNC2002, 03-06.06.2002
O-PFN2
By P.Cerello
Roberto Barbera
Dipartimento di Fisica dell’Università di Catania and INFN Catania - Italy
ALICE Collaboration
Summary and conclusions
Due to its huge needs in terms of distributed
computing power and mass storage grids are for
ALICE not just an interesting computer science
technology but a real “conditio sine qua non”.
Grid activities at ALICE are successfully
developing since almost two years already.
Since the beginning the ALICE attitude has been
very positive and “propositive”.
If you want to see ALICE jobs running on the
grid come to the DataGrid stand in the
demonstrations’ area.
TNC2002, 03-06.06.2002
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Roberto Barbera