The CERN Advanced STORage manager (CASTOR) is a hierarchical storage management system developed at CERN for physics data files. Files can be stored, listed, retrieved and remotely accessed using CASTOR command-line tools or user applications developed against the CASTOR API. CASTOR provides a set of access protocols such as RFIO (Remote File IO), ROOT, XROOT and GridFTP.

The design is based on a component architecture using a central database to save guard the state changes of CASTOR components. The access to disk pools is controlled by the Stager; the directory structure is kept by the Name Server. The tape access (write and recalls) is controlled by the Tape Infrastructure.      The 5 major functional modules are:

• Stager: disk pool manager (allocating and reclaiming space; controlling client access; disk pool local catalogue)
• Name Server: CASTOR name space (files and directories) including the corresponding file metadata (size, dates, checksum, ownership and ACLs, tape copy information). Command-line tools modelled along Unix tools allows to manipulate the name space (e.g. nsls corresponds to ls, etc...)
• Tape Infrastructure: under given conditions CASTOR saves files on tape. This is needed to provide data safety and to manage data storage larger than the available disks
• Client: it allows you to upload, download, access and manage CASTOR data.
• Storage Resource Management: it provides data access in a computing Grid via the SRM protocol. It interacts with CASTOR on behalf of a user or other services (as FTS, the File Transfer System used by the LHC community to export data).

Under construction

• Architecture page (documents and presentations)
• Software page (old web page)
• Development bug tracker