Specify the path name and filename location of the primary database datafiles followed by the standby location. This parameter converts the path names of the primary database datafiles to the standby datafile path names. If the standby database is on the same system as the primary database or if the directory structure where the datafiles are located on the standby site is different from the primary site, then this parameter is required. Note that this parameter is used only to convert path names for physical standby databases. Multiple pairs of paths may be specified by this parameter.I've got data guard running on two sites which are physically separate to the primary site. At one site we have the same paths for the data files so we have nothing for the db_file_name_convert parameter. At the other site we have different paths so we specify the full path of the primary, followed by the full path of the standby. Just the way that I have in the example above.