If set to a value greater than 0, multipathd will watch paths and check how many times a path has been failed due to errors.If the number of failures on a particular path is greater then the san_path_err_threshold, then the path will not reinstate till san_path_err_recovery_time. These path failures should occur within a san_path_err_forget_rate checks, if not we will consider the path is good enough to reinstantate.