Speaker
Mr
Tigran Mkrtchyan Mkrtchyan
(Deutsches Elektronen-Synchrotron DESY)
Description
Starting June 2007, 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 CITI-UMICH September 2006, dCache has proven to be compatible to all existing
clients. At the time of this presentation, at least two production level
installations are available. The one for the DESY, H1 experiment and for the Tier 2
center at University of Michigan. The official production version will be available
as soon as the NFSv4.1 protocol has been released.
Primary author
Mr
Tigran Mkrtchyan Mkrtchyan
(Deutsches Elektronen-Synchrotron DESY)
