A scalable infrastructure indexes and tracks media data and metadata in a distributed, multi-user system. An indexer is associated with particular storage locations, such as a disk, or a directory on a disk, to maintain an index of media files or metadata stored in those storage locations. The indexer monitors activity on any storage location with which it is associated. Any additions, deletions or modifications to files in that storage location cause the indexer to update its index. This index then can be accessed by any of a number of applications in the same manner as conventional indexes. There may be different indexers for different storage locations. Separate indexers may be provided for media files and compositions that use those media files.