When space is needed, the server reclaims space occupied by cached files. Files that have the oldest retrieval date are overwritten first.
For example, assume that two files, File A and File B, are cached files that are the same size. If File A was last retrieved on 05/16/08 and File B was last retrieved on 06/19/08, then File A is deleted to reclaim space first.
If you do not want the server to update the retrieval date for files when a client restores or retrieves the file, specify the server option NORETRIEVEDATE in the server options file. If you specify this option, the server removes copies of files in cache regardless how recently the files were retrieved.