12C中使用DG BROKER添加备库时报错提示：
DGMGRL> add database standby as connect identifier is standby;
Error: ORA-16831: operation not allowed on this member
Failed.
百度原因：添加使用的是备库控制文件
百度提供的解决办法：
在主库生成Far Sync的控制文件，拷贝到备库还原
主库生成控制文件
SQL> ALTER DATABASE CREATE FAR SYNC INSTANCE CONTROLFILE AS '/home/oracle/control01.dbf';
Database altered.
SQL>
备库还原
RMAN> restore controlfile from '/home/oracle/control01.dbf';
mount数据库并查看备库角色
SQL> select database_role,name,db_unique_name from v$database;
DATABASE_ROLE NAME DB_UNIQUE_NAME
-------------------------------- ------------------ ------------------------------------------------------------
FAR SYNC RACDB STANDBY
主库重新添加成功
DGMGRL> add far_sync standby as connect identifier is standby;
far sync instance "standby" added