1. INFSO-RI-508833 Enabling Grids for E-sciencE www.eu-egee.org Agreement Service for Storage Space Reservation T.Ferrari, E.Ronchieri JRA1 All Hands Meeting, Brno, June 20-22 2005

2. Enabling Grids for E-sciencE INFSO-RI-508833 Outline Architecture overview Implementation status Example of Agreement Offer for Storage Space Reservation Short and long-term work plan

3. Enabling Grids for E-sciencE INFSO-RI-508833 Agreement Service Architecture 1/2 gLite Allocation and Reservation Architecture http://edms.cern.ch/document/508055 (v. 2.1) Components: –Agreement offer: the “description” of the requested reservation –Agreement Initiator  e.g. WMS Reservation Manager/Data Scheduler/User –Agreement Service  Checks compliance of the offer to internal templates  Can interact with one or more types of resource reservation service providers (network – e.g. JRA4 bandwidth advance reservation, storage – e.g. StoRM, computing - ?) –Resource reservation Service Provider  Enforces the reservation on a specific resource instance

4. Enabling Grids for E-sciencE INFSO-RI-508833 Agreement Service Architecture 2/2 Agreement InitiatorAgreement Initiators Agreement Offer Storage/Computing/ Network Agreement Service Reservation and Allocation Service Providers

5. Enabling Grids for E-sciencE INFSO-RI-508833 Implementation 1/3 initiator Storage Space Reservation Agreement Service Storage Element (StoRM, SRM v2.1) Agreement Service operations: - createAgreement() - getTemplates() - getAgreementProperties() - agreementKill() - getAgreementStatus() createAgreement() srmReserveSpace()

6. Enabling Grids for E-sciencE INFSO-RI-508833 Implementation 2/3 Agreement service: –based on WS-Agreement XML Schema Definitions (GGF, GRAAP WG) –... but list of operations exposed is different (no WSRF) –gSOAP 2.7.0 –agreement service tested with StoRM (SRM v 2.1) –Current AS code in HEAD ( org.glite.allocation )

7. Enabling Grids for E-sciencE INFSO-RI-508833 Implementation 3/3 StoRM [1] –provides direct access into storage system, must reserve space directly into File System –based on GPFS File System features for pre-allocation –uses gpfs_prealloc( ) subroutine for space allocation  “The gpfs_prealloc( ) function is used to preallocate disk storage for a file that has already been opened, prior to writing data to the file. The preallocated disk storage is started at the requested offset, StartOffset, and covers at least the number of bytes requested, BytesToPrealloc. Allocations are rounded to GPFS subblock boundaries.”  “Disk space pre-allocation for a file provides an efficient method for allocating storage without having to write any data. This can result in faster I/O compared to a file which gains disk space incrementally as it grows.” –assigns a desired number of empty blocks (from free blocks table of FS) to a certain I-Node prior to writing to the file –space created identified by a token (i.e., handler) –for every srmPrepareToPut call with a certain space handler, the space previously created is partitioned to the desired size and an endpoint to a file with desired amount of pre-allocated blocks is returned [1] Zappi, R. et al. “StoRM: grid middleware for disk resource management”; in Proc. of the Conference on Computing in High Energy and Nuclear Physics (CHE0P 2004), Interlaken, CH, Sep 2004, Vol. 2, pp. 1238-1242

8. Enabling Grids for E-sciencE INFSO-RI-508833 Space reservation agreement offer (extract) 1/2 <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:resourceType"> StorageElement <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:serviceProviderURI"> http://testbed006.cnaf.infn.it/storm_0.2/services/SpaceService2 <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:serviceProviderURI"> http://testbed006.cnaf.infn.it/storm_0.2/services/SpaceService1

9. Enabling Grids for E-sciencE INFSO-RI-508833 Space reservation agreement offer (extract) 2/2 <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:duration"> 2000 <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:typeOfSpace"> durable <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:sizeOfTotalSpaceDesiredInBytes"> 2000000 <ns3:ServiceDescriptionTerm xsi:type="ns3:ServiceDescriptionTermType" ns3:ServiceName="spaceManagement:sizeOfGuaranteedSpaceDesiredInBytes"> 100000000

10. Enabling Grids for E-sciencE INFSO-RI-508833 Short-term future work Improvement of error handling Study of best deployment model for the Agreement Service Implementation of new operations –getAgreementStatus (srmGetSpaceMetaData) –agreementKill (srmReleaseSpace) –getAgreementProperties && getTemplate –updateAgreement (srmUpdateSpace, srmChangeFileStorageType) Integration with WMS –ISM extension (SE, agreementService schema) –Matchmaking –Agreement monitoring through LB

11. Enabling Grids for E-sciencE INFSO-RI-508833 Long-term future work Authorization Performance testing Integration with JRA4 Bandwidth Advance Reservation (BAR) and Network Service Access Point (NSAP)