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Proposal for a Dynamic Megatable

Proposal for a Dynamic Megatable. Flavia Donno CERN/IT. Tier-2 Sites & Capacities. A little difficult to determine exact resources installed in the Tier2s;  must be improved. (Ian Bird, March LCG OB).

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Proposal for a Dynamic Megatable

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  1. Proposal for a Dynamic Megatable Flavia Donno CERN/IT WLCG Grid Deployment Board, CERN 9 July 2008

  2. Tier-2 Sites & Capacities • A little difficult to determine exact resources installed in the Tier2s;must be improved (Ian Bird, March LCG OB) • But is provided < pledged because of availability or lack of use? need better reporting • M.C. Vetterli GDB presentation

  3. The requirements • The goal • Provide the management with information about installed capacity (per VO). • Provide the management with information about resource usage (per VO). • This info can also be used by VO operations people in order to "monitor" their usage of the resources • Main focus • Storage resources • Computing resources • Dynamic view • Information should be retrieved as dynamically as possible in order to be reliable • The information will be made available through the WLCG accounting system • Use the information system as source WLCG Grid Deployment Board, CERN 9 July 2008

  4. The documentation • The technical specifications are available in the CCRC twiki in the SSWG section: https://twiki.cern.ch/twiki/bin/view/LCG/WLCGCommonComputingReadinessChallenges#Storage_Solution_Working_Group_S • Storage only: • The documentation available reports on the conclusions reached during focused meetings with developers and information providers • Specific solutions found to cover dCache internal specialized buffers and avoid double counting • The document has been agreed by storage developers, storage information providers, data management developers, … WLCG Grid Deployment Board, CERN 9 July 2008

  5. The Storage Resources • Current accounting harvests data from BDII • … but many errors in data. • combination of Glue1.2 and 1.3 • Need to improve information providers and configuration. • Existing Reports • Current status (last hour) • Monthly Report (like manual Tier1 • reports). WLCG Grid Deployment Board, CERN 9 July 2008

  6. The Storage Resources • Use GlueSA class • It describes a Storage Area: logical view of a portion of space (can include disks and tapes) • Online resources only for the moment • GlueSAs do not overlap. • Shared spaces can be represented with one GlueSA with multiple GlueSAAccessControlBaseRule • A GlueSA can be published for unreserved space as well • In this case Total=Reserved Size (see later) • GlueSA can have one or more VOInfo associated objects • VOInfoTag is optional • The VOInfo object can be used to publish the path associated to a VO using the associated GlueSA (in case of shared SAs) WLCG Grid Deployment Board, CERN 9 July 2008

  7. The Storage Resources • GlueSA Sizes • GlueSAReservedOnlineSize • Space physically allocated to a VO (or a set of VOs) – Installed capacity • GlueSATotalOnlineSize (in GB = 109 bytes) • Total Online Space available at a given moment (it does not account for broken disk servers, draining pools, etc.) • GlueSAUsedOnlineSize (in GB = 109 bytes) • Size occupied by files that are not candidates for garbage collection – Resources usage • For Castor this is equal to GlueSATotalOnlineSize for T1D0 (they differ for T0D1) • GlueSAFreeOnlineSize (in GB = 109 bytes) • Free = Total - Used • GlueSACapability • Key/value pair to publish agreed characteristics of Storage Area, i.e. access=read, network=WAN-LAN, etc. • Experiments can use this field to select dCache pools WLCG Grid Deployment Board, CERN 9 July 2008

  8. Storage: Status and plans • Dynamic information providers for CASTOR by J. Jensen • Corrections needed to comply with agreement • Packaging and distribution effort through the CASTOR CVS • First installation foreseen at CERN • Availability: end of July 2008? • Dynamic information providers for dCache available by R. Trompert • Need to verify with dCache developers that pinned files usage info is available, and other details • 2-3 weeks to implement the proposal • The changes will be reflected also in the new official dCache information providers by P. Millar WLCG Grid Deployment Board, CERN 9 July 2008

  9. Storage: Status and plans • Dynamic information providers for DPM by Michel Jouvin • The proposal has been already implemented • Installed at Edinburgh – Testing phase started • Information already available for StoRM by developers • Probable minor additions for VOInfoPath • Need to work with OSG and NorduGrid WLCG Grid Deployment Board, CERN 9 July 2008

  10. The Computing Resources Pledges expressed in terms of KSI2000 per federation in current Megatable Use availableinformation published in BDII about installed capacity Red=deprecated 10 WLCG Grid Deployment Board, CERN 9 July 2008

  11. The Computing Resources • Ongoing work to make published information about installed capacity more reliable (see presentation of Steve Traylen at GDB) • Current tools publish always 1 GlueCluster and 1 GlueSubCluster when a GlueCE is published (problematic CPU counting) • Difference between SubCluster PhysicalCPUs and GlueCETotalCPUs • Is Subcluster PhysicalCPUs coherent with SubCluster Host BenchmarkSI00? • When SubCluster PhysicalCPUs=0 consider GlueCETotalCPUs: Number of slots per queue. Compatible with Subcluster Host BenchmarkSI00? Is this number correct (extracted from batch system)? • VOView TotalCPUs deprecated. Difficult to guess VO shares. WLCG Grid Deployment Board, CERN 9 July 2008

  12. Computing Resources Example • Need to interpret results • Refinement and cleaning (discrepancy between SubClusters and GlueCE, CPUs vs. cores, HEP only, etc.) • Improve information providers (Glue 2.0 helps) Double-counted Resources WLCG Grid Deployment Board, CERN 9 July 2008

  13. Computing: Status and plans • Computing resources • First procedures in place. Looking for better technologies to make results available. • We are currently in the process of understanding and refining information • Work with sites • Check that needs are covered by Glue 2.0 • Help automate the publishing process • Work with OSG and NorduGrid • Provide a working prototype for APEL by the end of August 2008 • Give feedback to GDB and MB • Help producing monthly reports WLCG Grid Deployment Board, CERN 9 July 2008

  14. Thank You WLCG Grid Deployment Board, CERN 9 July 2008

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