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PHENIX Computing

PHENIX Computing. Sangsu Ryu. RHIC PHENIX 실험의 목적. QCD 에 의하면 쿼크는 독립적으로 존재할 수 없고 다른 쿼크와 합쳐 color singlet 상태인 강입자로 존재 => 색 속박 현상 Lattice QCD: 극한 상태의 핵 물질에서 색 속박이 풀린 쿼크 - 글루온 플라즈마 (QGP) 상태로 상전이 를 예측. 빅뱅 직후 수 μs 동안 초기의 우주물질은 쿼크 - 글루온 플라스마 상태 => 초기 우주상태의 실험실 재현. RHIC.

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PHENIX Computing

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  1. PHENIX Computing Sangsu Ryu

  2. RHIC PHENIX 실험의 목적 QCD에 의하면 쿼크는 독립적으로 존재할 수 없고 다른 쿼크와 합쳐 color singlet 상태인 강입자로 존재 => 색 속박 현상 Lattice QCD: 극한 상태의 핵 물질에서 색 속박이 풀린 쿼크-글루온 플라즈마(QGP)상태로 상전이 를 예측 빅뱅 직후 수 μs 동안 초기의 우주물질은 쿼크-글루온 플라스마 상태 => 초기 우주상태의 실험실 재현

  3. RHIC • Configurations: Two concentric superconducting magnet rings (3.8Km circumference) with 6 interaction regions • Ion Beams: Au + Au (or p + A) • s = 200 GeV/nucleon • luminosity = 21026 cm-2 s-1 • Polarized proton: p + p •  s = 500 GeV • luminosity = 1.4 1031 cm-2 s-1 •  Experiments: PHENIX, STAR, PHOBOS, BRAHMS

  4. PHENIX Experiment  Physics Goals Search for Quark-Gluon Plasma Hard Scattering Processes Spin Physics  Experimental Apparatus PHENIX Central Arms (e, , hadrons) PHENIX Muon Arms ( )

  5. MVD (Multiplicity Vertex Detector) • MVD • Charged particle multiplicity • Event characterization • Reconstruction of collision vertex with 100 μm accuracy • dNch/dηdΦ • Silicon Detectors • Strips • 200 μm pitch, 64cm long • Pads a z=+/-35cm • High granularity with 34,816 channels

  6. MVD Silicon Detector Pads Strips

  7. MVD Software • Offline software • Charged particle multiplicity • dNch/dη • Reconstruction of collision vertex • Simulation (GEANT3) • Detector response • Online monitor

  8. PHENIX Data Size • Peak DAQ bandwidth in PHENIX is 20 MB/sec. • Ion Beams (Au + Au) 1. Minimum bias events (0.16 MB/event): • Raw event rate = 1400 Hz (224 MB/sec) • Trigger rate = 124 Hz (20 MB/sec) • 2. Central events (0.4MB/event): • Trigger rate = 50 Hz (20 MB/sec) • Polarized proton (p + p) • All events (25 KB/event): • Raw event rate = 250 KHz (6250 MB/sec) • Trigger rate = 800 Hz (20 MB/sec)

  9. PHENIX Computing Software • Simulation (PISA) • GEANT3 (in Fortran) • Reconstruction • PHOOL (modified ROOT) framework • C++ • Online monitor • Software management • CVS • Rebuild • Daily rebuild • Batch server • LSF • Event display • Database • Calibration : Objectivity, postgreSQL • Datacarousel : postgreSQL

  10. RCF • RHIC Computing Facility (RCF) provides computing facilities for four RHIC experiments (PHENIX, STAR, PHOBOS, BRAHMS). • Typically RCF gets ~ 30 MB/sec (or a few TB/day) from the PHENIX counting house only through Gigabit network. Thus RCF is required to have complicated data storage and data handling systems. • RCF has established an AFS cell for sharing files with remote institutions and NFS is the primary means through which data is made available to the users at the RCF. • The similar facility is established at RIKEN (CC-J) as a regional computing center for PHENIX. • Compact but effective system is also installed at Yonsei.

  11. Mining & Staging PHENIX Computing System • Linux OS with ROOT • C++ class library (PHOOL) based on top of ROOT • GNU build system • Database (Objectivity OODB, postgreSQL) • calibration 자료, 파일 목록, run 정보, etc. • 연간 ~100 GB의 calibration 자료 Big Disk Pretty Big Disk HPSS Raw Data Raw Data DST Data Analysis Jobs Counting House Reconstruction Farm Calibrations & Run Info Local Disks Tag DB Database

  12. Data Carousel using HPSS • To handle annual volume of 500TB from PHENIX only, High Performance Storage System (HPSS) is used as Hierarchical Storage system with tape robotics and disk system. • IBM computer (AIX4.2) organizes the request of users to retrieve data without chaos. • PHENIX used ten 9840 and eight 9940 drives from STK. • The tape media costs about $1/GB.

  13. Data carousel architecture HPSS tape data mover “ORNL” software carousel server mySQL database HPSS cache filelist client rmine0x pftp pftp CAS NFS disk CAS local disk

  14. Disk Storage at RCF • The storage resources are provided by a group of SUN NFS servers with 60TB of SAN based RAID arrays backed by a series of StorageTek tape libraries managed by HPSS. • Vendors of storage disks are Data Direct, MTI, ZZYZX, and LSI.

  15. Linux Farms at RCF • CRS (Central Reconstruction Server) farms are dedicated to the processing of raw event data to generate reconstructed events (strictly batch systems without being available for general users). • CAS (Central Analysis Server) farms are dedicated to the analysis of the reconstructed events (mix of interactive and batch systems). • The LSF, the Load Sharing Facility, manages batch jobs. • There are about 600 machines (dual CPU, IGB memory, 30GB local disks) at RCF and about 200 machines are allocated for PHENIX.

  16. offline software technology • analysis framework • C++ class library (PHOOL) based on top of ROOT base class for analysis modules • “tree” structure for holding, organizing data can contain raw data, DSTs, transient results • uses ROOT I/O • database • using Objectivity OODB for calibration data, file catalog, run info, etc. expecting ~100 GB/year of calibration data • code development environment • based heavily on GNU tools (autoconf, automake, libtool)

  17. PHENIX CC-J • The PHENIX CC-J at RIKEN is intended to serve as the main site of computing for PHENIX simulations, a regional Asia computing center for PHENIX, and as a center for SPIN physics analysis. • In order to exchange data between RCF and CC-J, a proper bandwidth of the WAN between RCF and CC-J is required. • CC-J has CPU farms of 10K SPECint95, tape storage of 100 TB, disk storage of 15 TB, tape I/O of 100 MB/sec, disk I/O of 600MB/sec, and 6 SUN SMP data server units.

  18. Situations at YONSEI • Comparable mirror image into Yonsei by “Explicit” copy of the remote system • Usage of the local cluster machines Similar operation environment (same OS, and similar hardware spec) 1. Disk sharing through NFS One installation of analysis library and sharing by other machines 2. Easy upgrade and management • Local clustering Unlimited network resources between the cluster machines by using 100Mbps Current number of the cluster machines = 2 (2CPUs) + 2 (as RAID) • File transfers from RCF Software update by copying shared libraries (once/week, takes less than about 1 hour) Raw data copy using “scp” or BBFTP (~1GB/day)

  19. Yonsei Computing Resources Yonsei Linux boxes for PHENIX analysis use • 4 desktop boxes in a firewall (Pentium III/IV) Linux (RedHat 7.3, Kernel 2.4.18-3, GCC 2.95.3) ROOT(ROOT 3.01/05) • One machine has all software required for PHENIX analysis • Event generation, reconstruction, analysis • Remaining desktops share one library directory via NFS • 2 large RAID disk box with several IDE HDDs (~500G X 2) and several small disks (total ~500G) in 2 desktops • Compact but effective system for small user group

  20. Yonsei Computing Resources • Linux (RedHat 7.3, Kernel 2.4.18-3 ,GCC 2.95.3) • ROOT(ROOT 3.01/05) Gateway Firewall Big Disk(480G X 2) RAID tools for Linux PHENIX Library 100Mbps P3 1G Raw Data & DST Library(NFS) OBJY P3 1G Analysis Jobs Reconstruction P4 2G 480G DISK Calibrations & Run Info Tag DB P4 1.3G 480G RAID DISK Database

  21. Belle Monte-Carlo Production • Goals • Monte Carlo event production • Analysis • Computing System • Gateway and firewall • 24 cpus, ~5TB disks • 1 Gbps intra network • Servers and clients • Library, database, storage

  22. Belle MC Cluster Intranet Internet 1Gbps Switching Hub 1Gbps Fiber 1Gbps Copper 1Gbps Copper 1Gbps Copper 1Gbps Copper 1Gbps Copper 1Gbps Copper 1Gbps Copper Gateway Masquerade Firewall Analysis Server Analysis Server eth0 eth1 Belle Library Server Belle Database Server System Server Analysis Server

  23. Hardware

  24. Belle Cluster Servers • Automated OS installation • DHCP/BOOTP • TFTP • NFS or FTP • System administration • 사용자 관리를 위한 NIS • 파일 공유를 위한 NFS • Belle 라이브러리 • NFS 를 통한 파일 공유 • 자료파일 • NFS를 통한 파일 공유 • Belle 데이터베이스 • PostgreSQL 서버

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