The LCG File catalogue (LFC) is a server that gives services of file metadata store and replica location. It is one of the first components that have been designed for the purpose of Grid Data Management.
LFC offers a hierarchical view of files to users, with a UNIX-like semantics. The LFC catalogue provides:
- Logical File Name (LFN) to Storage URL (SURL) mappings;
- Authorisation on its logical namespace, based on UNIX file modes, POSIX ACLs and various kinds of strong authentication, including X509.
LFC uses a proprietary binary communication protocol, based on TCP. The LFC client encapsulates the communication protocol into an API that can be used by applications.
The LFC server, entirely written in C, communicates with a database (either Oracle or MySQL), where all the data is stored. The LFC server is accessible on the client side via:
- A set of commands to be run from a shell
- The C API of its client
- A Python interface and a Perl interface;