Speaker
Mr
Luca Magnoni
(INFN-CNAF)
Description
In a Grid environment the naming capability allows users to refer to specific data
resources in a physical storage system using a high level logical identifier. This
logical identifier is typically organized in a file system like structure, a
hierarchical tree of names. Storage Resource Manager (SRM) services map the logical
identifier to the physical location of data evaluating a set of parameters as the
desired quality of services and the VOMS attributes specified
in the requests.
StoRM is a SRM service developed by INFN and ICTP-EGRID to manage file and space on
standard POSIX and high performing parallel and cluster file systems.
An upcoming requirement in the Grid data scenario is the orthogonality of the logical
name and the physical location of data, in order to refer, with the same identifier,
to different copies of data archived in various storage areas with different quality
of service.
The mapping mechanism proposed in StoRM is based on a XML document that represents
the different storage components managed by the service, the storage
areas defined by the site administrator, the quality of service they provide and the
Virtual Organization that want to use the storage area.
An appropriate directory tree is realized in each storage component reflecting the
XML namespace schema.
In this scenario StoRM is able to identify the physical location of a requested data
evaluating the logical identifier and the specified attributes following the XML
schema, without querying any database service.
This paper presents the namespace schema defined, the mapping mechanism and the
technical details of the StoRM implementation.
Primary authors
Dr
Alberto Forti
(INFN-CNAF)
Mr
Ezio Corso
(ICTP-EGRID)
Mr
Luca Magnoni
(INFN-CNAF)
Mr
Riccardo Zappi
(INFN-CNAF)
