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WP5 Storage Element

WP5 Storage Element. DataGrid Project Conference Heidelberg, 26 Sep-01 Oct 2003. Intro. WP5 mission was to provide a common API to Mass Storage People as why it is so complicated … because we provided a common API to Mass Storage And because we followed the SRM interface. More about SRM.

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WP5 Storage Element

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  1. WP5 Storage Element DataGrid Project Conference Heidelberg, 26 Sep-01 Oct 2003

  2. Intro • WP5 mission was to provide a common API to Mass Storage • People as why it is so complicated • … because we provided a common API to Mass Storage • And because we followed the SRM interface

  3. More about SRM • Users know Site File Names (SFN) or Physical File Names (PFN) • lxshare0408.cern.ch/bongo/mumble SE cache file request id Disk cache MSS file

  4. More about SRM • Client queries the status of a request • Better that client polls than server callbacks • Server (ideally) able to give time estimate SE status? “not ready, try later” Disk cache MSS file

  5. More about SRM • When request is ready, client gets a Transfer URL (TURL) • gsiftp://lxshare0408.cern.ch/flatfiles/01/data/16bd30e2a899b7321baf00146acbe953 SE status? ready: TURL Disk cache MSS file file

  6. More about SRM • Client accesses the file in the SE’s disk cache using (usually) non-SE tools SE Disk cache MSS globus- url-copy file file file

  7. More about SRM • Finally, client informs SE that data transfer is done • This is required for cache management etc SE done ok Disk cache MSS file file

  8. EDG-SE in TB2.0 • SE Control System delivered as webservice • Provides common (blocking) interface to all SEs • Disk and several MSS • Publishes GLUE Storage Schema to Information Service (RGMA) • MSS supported • Castor, HPSS, ADS, disk • Protocols supported • Gridftp, file, rfio • Each VO has its own name space • WP9 use case

  9. Sites • Tested in application testbed • Barcelona(Castor), NIKHEF, Imperial, RAL-Tier1(ADS), RAL-PP, Karlsruhe, CC-IN2P3 Lyon • Tested in 2.0 dev testbed but not yet integrated in app testbed • CERN (Castor), CC-IN2P3 (HPSS) • Under development but not in TB2.1 • ESRIN – AMS • SARA – SGI • INSA - Dicom

  10. Protocols • SE returns Transfer URL (TURL) for requested protocol • GridFTP(gsiftp) can be used for data transfer to remote SE • File transferred using globus-url-copy • FILE protocol provides access to disk on ‘local’ SE from WN when WSE filesystems nfs-mounted on WN • TURL= file://pathname • rfiod runs on all Ses and clients on WNs • TURL= rfio://host/path (not hostname:/pathname)

  11. WP9 Migration • Other applications didn’t want to migrate data from TB1 • WP9 had 11,000 files dstributed round TB1.4 • Use as a migration test case without physically moving files • WP2 tool migrates TB1 Replica Catalogue to RLS • And checks existence of files. • WP5 tool run by sysadmins at each site to register files in TB2.0 SE • Plan extended due to sysadmins wanting to move files from TB1.4 locations • Migration still running last night

  12. EDG-SE in TB2.1 • Bug fixes • Delete • More efficient ls to speed up edg-rm registration • Secure mode SE • User identified by DN • VO taken from gridmapfile • cf insecure mode where all files owned by a site-defined user (default John Gordon)

  13. Ready for demo Developments completed but not released in TB2.1 • ACL • Using GACL • SRM1.1 for GFAL • Implemented subset of SRMv1.1 used by GFAL spec • Grid File Access Library being developed by CERN for LCG • Implemented as adaptor class on TB2 SE

  14. Will be ready for demo • Asynchronous (non-blocking) SE • Full SRM v1.1 • As separate direct webservice • VOMS support • Groups, roles, etc • Already supported by GACL • Use edg-authorisation-manager to parse VOMS credentials • Disk Cache Management

  15. Future Directions – post EDG • Sell to LCG • For SRM and VOMS access to MSS • Guaranteed reservations • SRM2 recommendations: volatile, durable, permanent files and space • Full SRM version 2.1 • Scalability • Scalability will be improved by making a single SE distributed

  16. Outro • I am retiring as WP Manager • Being replaced by Jens Jensen • So long and thanks for all the fish!

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