Mr Tigran Mkrtchyan Mkrtchyan (Deutsches Elektronen-Synchrotron DESY)
Starting spring 2009, all WLCG data management services have to be ready and prepared to move terabytes of data from CERN to the Tier 1 centers world wide, and from the Tier 1s to their corresponding Tier 2s. Reliable file transfer services, like FTS, on top of the SRM v2.2 protocol are playing a major role in this game. Nevertheless, moving large junks of data is only part of the challenge. As soon as the LHC experiments go online, thousands of physicists across the world will start data analysis, to provide first results as soon as possible. At that point in time, local file access becomes crucial. Currently, large numbers of local file access protocols are supported by various Storage Systems – dcap, gsidcap, rfio-dpm, rfio-castor, http and xrootd. A standard protocol, usable by any unmodified application, assuming POSIX data access, is highly desirable. The NFSv4.1 protocol, defined by IETF and implemented by various Operating System and Storage Box vendors, e.g. EMC, IBM, Linux, NetApp , Panasas and SUN, provides all necessary functionality: security mechanism negotiation (GSS-API, GSI, X509, UNIX), data access protocol negotiation (NFSv4 mandatory), clear distinction between metadata ( namespace ) and data access, support of multiple dataservers, ACLs, client and server crash recovery and much more. The client modules are being developed for AIX, Linux, and the Solaris kernels. NFSv4.1 is an open standard, industry backed protocol which easily integrates into the dCache architecture. Together with the new namespace provider, Chimera, dCache provides a native NFSv4.1 implementation. At the most recent NFS “Bakeathon” at SUN-Microsystems September 2008, dCache has proven to be compatible to all existing clients. At the time of this presentation, standard NFSv4.1 client will be a pert of Linux kernel distribution. Starting dCache release 1.9.3, scheduled for January 2009, NFSv41 support will be included.