LFC Server LCG File Catalog

1
LFC Server(LCG File Catalog)
Yoshiyuki Watase CRC,KEK
2
File naming convention in LCG

• Grid file must be exist physically and registered
  to the catalog.
• GUID(Grid Unique Identifier ) Files in the LCG
  must be identified uniquely in the Grid world.
• guidlt40_bytes_unique_stringgt
• guid295fert0-6799902--bakdsg
• LFN(Logical File Name) User alias of the file
• lfn/grid/ltmyVOgt/
• lfn/grid/apdg/watase/testfile
• PFN(Physical file name) indicates the physical
  location and its access features. Also used as
  SURL(Storage URL)
• sfn//ltSE_hostnamegt/ltstringgt for storage
  element without SRM
• sfn//dgsexx.cc.kek.jp/flatfiles/apdg/
• srm//ltSE_hostnaemgt/ltstringgt for storage
  element with SRM
• srm//caster.cern.ch/caster/vo/

SRM Storage Resource Management interface
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LFC Architecture

• Relations between LFN ,GUID, and PFN are stored
  and managed with a relational database backend
  mysql.
• Global hierarchical namespace of LFN is mapped to
  GUIDsGUIDs are mapped to physical locations of
  file replicas.Multiple LFNs are allowed as
  symbolic links to the primary LFN.
• Each VO has a central LFC server with distributed
  local servers.
• Multi-threaded daemon is implemented for bulk
  operation.
• LFC database must be installed in the reliable
  machine and backuped.

Replicas
Lfn/grid/apdg/kek/data101.exp
GUIDxxxxxxxxx02
GUIDxxxxxxxxx01
GUIDxxxxxxxxx03
sfnse2..
Symbolic link
sfn/se3..
sfnse1..
Original
Lfn/grid/apdg/melb/data202.exp
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User interface for the catalog files

• Directory and metadata management
• lfc-ls, lfc-mkdir, lfc-setacl, lfc-setcomment
• File access methods
• lcg-utils command line interface similar to UNIX
• lcg-cr , ldg-cp, lcg-del, lcg-rep, lcg-aa,
• GFALGrid File Access Library to give a uniform
  POSIX interface to local and storage in the Grid.
• POOLaccess method for the persistent Objects
• Reference LCG-2 User Guide p.64 Data management

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Usage for a test

• Man page is availableman lcg-cr
• Directory listinglfc-ls l /grid/
• Make directorylfc-mkdir /grid/apdag/user1
• Copy a local file to a SE and register it in the
  catalog (upload)lcg-cr vo apdg d
  dgxxse.cc.kek.jp l /grid/apdg/user1/exp01.dat
  file/home/user1/exp01.datlcg-cr n 10 vo apdg
  d dgxxse.cc.kek.jp l /grid/apdg/user1/exp01.dat
  file/home/user1/exp01.dat
• Copy a Grid file to a local destination
  (download)lcg-cp n 10 vo apdg
  lfn/grid/apdg/user1/exp01.dat file/home/user1/ex
  p01.dat
• Copy a file from one SE to another and register
  it in the replica cataloglcg-rep vo apdg d
  dgxxse2.cc.kek.jp srm//dgxxse.cc.kek.jp/dpm/cc.ke
  k.jp/home/apdg/..
• List the replicas for a given LFN, GUID, or
  SURLlcg-lr vo apdg lfn/grid/apdg/exp01.dat

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Site Config at KEK
cc.kek.jp
nodes
WNs
nodes
nodes
WNs
VOMS Server
LFC Server