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Scope of the project

The goal of this project is to provide a system for storing and retrieving huge amounts of data, distributed among a large number of heterogenous server nodes, under a single virtual filesystem tree with a variety of standard access methods. Depending on the Persistency Model, dCache provides methods for exchanging data with backend (tertiary) Storage Systems as well as space management, pool attraction, dataset replication, hot spot determination and recovery from disk or node failures. Connected to a tertiary storage system, the cache simulates unlimited direct access storage space. Data exchanges to and from the underlying HSM are performed automatically and invisibly to the user. Beside HEP specific protocols, data in dCache can be accessed via NFSv4.1 (pNFS) as well as through WebDav.
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News

Thursday September 9, a full day dCache tutorial is organized by the German dCache support group in the context of the International GridKa school of computing.
  • European Middleware Initiative, EMI started Mai 1. According to the EU Factsheet, the objectives of EMI are : The European Middleware Initiative brings together the major middleware providers in Europe to deliver a consolidated set of middleware components for deployment in EGI, PRACE and other Distributed Computing Infrastructures (DCIs). dCache is funded by EMI in the context of SA1 and JRA1 with 1.25 FTE.
  • dCache Articles
  • Security
    • dCache.org is introducing a new mailing list :
      security at dcache dot org
      dCache user should report problems or bugs to this list if there is the suspicion that the issue is security related or if the report may contain confidential information. (e.g. passwords). Only a very restricted number of people have access to this particular mailing list.
  • Newletters and announcements.
  • Chimera :
    In order to be prepared for the first year of LHC datataking, we recommend to upgrade the pnfs filesystem to chimera. Please checkout the migration instructions and give it a try. You can evaluate the entire migration procedure in a safe test environment. Some sites already started the migration end of last year. Up to know, the NDGF Tier I and about 10 dCache Tier II are operating chimera. No problems have been reported yet. More information is available from our documentation area. The main advantages of chimera are :
    • Chimera scales nicely with the hardware performance and the database backend.
    • You may run regular SQL queries to collect maintainance and monitoring information of the chimera filesystem.
    • File system ACL inheritance is only available with Chimera. With pnfs, newly created directory will get the default set of ACL's. With Chimera it will inherit its parent ACLs .
    Chimera upgrade schedule
    Tier 1's
    • NDGF : done
    • IN2P3 : done
    • gridKa
      • CMS : done
      • Atlas : done
    • SARA : done
    • Triumf : done
    • FERMI : scheduled : N/A
    • BNL : scheduled : N/A
    • PIC : scheduled : N/A
    Tier II's
    • DESY
      • Atlas : done
      • CMS : done
      • ILC, DESY-generic : done
      • H1 Resilient : done
      • Hera : done
    • Aachen : done
    • Wuppertal : done
  • The dCache wiki : In addition to the Book, we offer a wiki were you may find some more helpful information. Check the link to findout on how you can contribute to the wiki with advise, documentation or tools.

Releases

Golden Releases
The currently recommended Golden Release 1.9.5 will be supported for the duration of the 2010/2011 LHC run period. In parallel, the next Golden Release is planned for Feb 2011.


Supported and expected Releases
  • 1.9.9 pre-production.
  • 1.9.8 production, recommended
  • 1.9.7 production.
  • 1.9.6 is depricated.
  • 1.9.5 Golden Release will be supported for the duration of the 2010/2011 LHC run period.
  • 1.9.4 is depricated.
General Release Policy
  • Time Based Releases : The dCache project is moving away from feature based releases towards Time Based Releases. As the name already implices, this essentially means that we will be better in predicting when a release is being published. The drawback is that features which don't make it into the repository till some time before the release is due, just won't be part of that release. The advantage is that sites can do better planing in upgrading and that the synchronization with our distributors is eased.
Golden Release
  • Golden Release : The Golden Release (1.9.5) is meant to be maintained throughout the entire first round of LHC data taking.
  • Version 1.9.5 is out. Please make yourself familiar with the release notes. 1.9.5 includes :
    • File System Access Control Lists (ACL's), as already in 1.9.3.
    • The asynchronous srmLs, as already in 1.9.3.
    • Tape System Protection. This feature allows to restrict "Tape Read Access" to a white list of DN/FQANs.

Funding

Information, Contact, Mailing lists

Documentation : Publications, Presentations and more

dCache, the Book

More on mailing lists
Contact : or
More : The dCache wiki

Project Partners

dCache is a joint venture between the Deutsches Elektronen-Synchrotron, DESY, the Fermi National Accelerator Laboratory, FNAL and the Nordic Data Grid Facility, NDGF.

Project Status

Since end of 2001 our full production release is in use at an increasing number of sites world-wide and is delivering tera bytes of data from over hundreds of distributed server nodes.
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