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Appendix: Replica Manager for EDG Release 2 versus EDG Release 1
The current EDG Release 2 Replica Manager has some functionality
changes from the previous EDG Release 1 version (first released in May
2002) due to some important design changes. In this section we
describe a few differences between the two replica managers in order
to provide an easier start for people already familiar with the EDG
Release 1 edg-replica-manager. Whenever we use the program
name edg-replica-manager we refer to the old tool, and we use
the term edg-rm or EDG Replica Manager to refer to the new
replication tool.
Basically, the new interface is very similar to the old one. However,
there are more features added and more Grid services used. The
following list outlines the main differences.
- edg-rm uses the Replica Location Service (RLS) and the
Replica Metadata Catalog and thus there is no
restriction of the use of Logical File Names. The LFN can be any
user supplied string prefixed by lfn:. In addition, alias
names are allowed for LFNs.
- In addition to LFNs, GUIDs (Grid Universal Identifiers)
are uses to uniquely identify Logical File Names.
- For all physical filenames or site filenames, a protocol needs
to be added as a prefix. For edg-replica-manager the hostname alone
was sufficient but edg-rm also requires the protocol name in the
file name. Example:
edg-replica-manager (old):
copyAndRegisterFile -s host1.cern.ch/home/data/testfile
edg-rm:
copyAndRegisterFile gsiftp://host1.cern.ch/home/data/testfile
Also the protocol "file:" is allowed if a file is available locally.
- The command line interface (CLI) has changed slightly: instead
of having an executable for each method (edg-replica-manager),
edg-rm provides a single executable where the method is passed as
the first parameter.
edg-rm copyAndRegister
rather than
edg-replica-manager-copyAndRegister
edg-rm has one Java rather than several C++ executables.
- No direct MSS interface: The new Replica Manager uses the
SRM for that purpose
- The EDG Replica Manager package is a pure Java package and does not provide a C++ interface to the end user. A
limited C++ API is provided for the methods listReplicas and
getAccessCosts and is part of the edg-replica-manager-client package (C++
based).
- The new replica manager uses the Replica Optimization Services (ROS, also called
Optor) and thus provides several replica optization methods like
getBestFile, listBestFile, getAccessCost etc.
- registerFile/unregisterFile instead of registerEntry/unregisterEntry
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2004-06-14