oracle的ogg和dg服务（ORACLEDG主备切换最佳实践）

概况：Os，下面我们就来聊聊关于oracle的ogg和dg服务?接下来我们就一起去了解一下吧!

oracle的ogg和dg服务

概况：

Os	db	db_name	db_name	role
Rhel 6.10	Oracle 11G	rac	Demo	PRIMARY
Rhel 6.10	Oracle 11G	单实例	adgdemo	STANDBY

一、切换前状态检查

1、查看两边归档是否对得上

主库：

SQL> select max(SEQUENCE#) from v$archived_log where applied='YES'; MAX(SEQUENCE#) -------------- 63

备库：

SQL> select max(sequence#) from v$archived_log where applied='YES'; MAX(SEQUENCE#) -------------- 63

2、状态检查：

主库：

select switchover_status,open_mode,database_role from v$database; SWITCHOVER_STATUS OPEN_MODE DATABASE_ROLE -------------------- -------------------- ---------------- SESSION ACTIVE READ WRITE PRIMARY

备库：

SWITCHOVER_STATUS OPEN_MODE DATABASE_ROLE -------------------- -------------------- ---------------- NOT ALLOWED READ ONLY WITH APPLY PHYSI CAL STANDBY

二、切换DG

步骤：关闭：先主库，后备机

1.主库切换成备库，然后将原主库启动到物理库的状态

SQL> alter database commit to switchover to physical standby with session shutdown;

2.打开数据库nomount

SQL> startup nomount

3.更改主库为备库

SQL> alter database mount standby database;

4、单节点应用日志

SQL> alter database recover managed standby database disconnect from session;

5、将备库切换成主库

原主库已经关闭，注意原备库switchover_status已经切换为TO PRIMARY

SQL> select switchover_status,open_mode,database_role from v$database; SWITCHOVER_STATUS OPEN_MODE DATABASE_ROLE -------------------- -------------------- ---------------- TO PRIMARY READ ONLY WITH APPLY PHYSICAL STANDBY

6、切换转换standby 到primary 角色

SQL> alter database commit to switchover to primary;

7、完成转换，打开新的primary 数据库

SQL> alter database open;

三、原主库切换成备库

当前的备库是mount状态了，运行以下语句

1、取消日志的运用

SQL>alter database recover managed standby database cancel;

2、打开数据库

SQL> alter database open;

3、启用日志实时应用

alter database recover managed standby database using current logfile disconnect from session;