DG保护模式切换

本文主要是介绍DG保护模式切换，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

ADG三种模式切换及介绍
1.1切换到最大保护模式(PERFORMANCE-->PROTECTION)

--主库
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PERFORMANCE  PRIMARY		TO STANDBY
--备库
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PERFORMANCE  PHYSICAL STANDBY NOT ALLOWED
--主库操作
--切换到PROTECTION需要重启
alter database set standby database to maximize protection;
alter database set standby database to maximize protection
*
ERROR at line 1:
ORA-01126: database must be mounted in this instance and not open in any
instanceshu immediate
startup mount
alter database set standby database to maximize protection;Database altered.
alter database open;
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PROTECTION   PHYSICAL STANDBY NOT ALLOWED

1.2切换到最大可用模式(PERFORMANCE-->AVAILABILITY)

--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PERFORMANCE  PHYSICAL STANDBY NOT ALLOWED
--主库不需要重启
alter database set standby database to maximize availability;Database altered.
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM AVAILABILITY PHYSICAL STANDBY NOT ALLOWED

2.1切换到最大性能模式(AVAILABILITY-->PERFORMANCE)

--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM AVAILABILITY PHYSICAL STANDBY NOT ALLOWED
--主库操作
alter database set standby database to maximize performance;Database altered.
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PERFORMANCE  PRIMARY		TO STANDBY

2.2切换到最大保护模式(AVAILABILITY-->PROTECTION)

--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM AVAILABILITY PRIMARY		TO STANDBY
--主库操作不需要重启
alter database set standby database to maximize protection;Database altered.
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PROTECTION   PRIMARY		TO STANDBY

3.1切换到最大性能模式(PROTECTION-->PERFORMANCE)

--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PROTECTION   PRIMARY		TO STANDBY
--主库操作
alter database set standby database to maximize performance;Database altered.
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PERFORMANCE  PRIMARY		TO STANDBY

3.2切换到最大可用模式(PROTECTION-->AVAILABILITY)

--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM PROTECTION   PRIMARY		TO STANDBY
--主库操作
alter database set standby database to maximize availability;Database altered.
--主备库都是下面的输出（database_role肯定是有区别的）
select name,protection_mode,database_role,switchover_status from v$database;NAME	  PROTECTION_MODE      DATABASE_ROLE	SWITCHOVER_STATUS
--------- -------------------- ---------------- --------------------
ORCL	  MAXIMUM AVAILABILITY PRIMARY		TO STANDBY

总结
只有PERFORMANCE切换到PROTECTION模式的时候需要重启到MOUNT状态，其他的无论怎么切换都不需要重启；
还有就是要注意log_archive_dest_n中的参数，AVAILABILITY PROTECTION一定要是LGWR SYNC AFFIRM，PERFORMANCE可以是LGWR或者ARCH

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