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Storage Resource Manager. GridPP Workshop April 2010 Jens Jensen. Background. SRM is the Storage Resource Manager A Control protocol for Mass Storage Systems Standard Protocol in Open Grid Forum. Who Is Using It?. SRM was originally designed by HEP Storage interface for WLCG
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Storage Resource Manager • GridPP Workshop • April 2010 • Jens Jensen
Background • SRM is the Storage Resource Manager • A Control protocol for Mass Storage Systems • Standard Protocol in Open Grid Forum
Who Is Using It? • SRM was originally designed by HEP • Storage interface for WLCG • Includes EGEE and OSG (eg ESG) • EGEE brought first non-HEP users • Lots of EGEE VOs, e.g., Biomedical • Other non-HEP users, e.g. • ICTP: Financial • GridPP: industry (camont + total)
Storage Element Deployment 75 (53) 228 (174) 17 (18) 27 (3) 1? (1?) 43 (25) 12 (23) • dCache (DESY+FNAL) • DPM (CERN) • CASTOR (CERN+RAL) • BestMan (LBNL) • Jasmine (JLAB) • StoRM (ICTP-EGRID/INFN) • Undefined or local disk
What is a “Storage Element”? • Data Mgmt Metadata THE (gLite) GRID • Computing Storage Element Disk Pools Disk storage Disk storage Disk storage Tape storage
Where is the File LFN LFN LFN GUID Storage Elements SURL SURL SURL TURL Physical File Physical File Physical File Physical File
What is a “Storage Element” • Interface to mass storage systems • Part of a loosely coupled grid • Provide uniform (control) interface • Protect the storage system against the grid • Enable grid to efficiently use storage
What is a Storage Element? Used by EGEE, OSG,… Six-seven different implementations Information System Control Interface (SRM) Data Transfer Storage Element An SRM is a “Storage Element” but not vice versa GIN: Use SRB as Storage Element
What is SRM? • Control API • Implemented in SOAP over GSI • Protocol is asynchronous • In principle anything can be async • But can be implemented sync • Client polls status of request • Design for MSS, clients can be held
Implementations • Servers not necessarily optimal implementations • eg srmPrepareToGet() • They interoperate in WLCG core • Clients implemented against servers • Instead of against spec
Tech • ~7 interoperating implementations • One is only SRM1 • CASTOR only provides SRM2 • Most (all?) Open Source, some not • Using SOAP over GSI sockets • Delegation needed for srmCopy • No WS-Anything
Transfer/Access Protocols • Only GridFTP is common AP • HTTP(S) is potential • LAN (insecure) or LAN (secure) vary • Eg RFIO, DCAP,