Oracle 11g 一主多备切换方案
最近公司需要把核心两节点RAC从虚拟化环境迁移至物理机,考虑停机时间要求比较短并且还有两个备库存在,决定使用RAC到RAC的备库使用switch over的方式进行迁移。原RAC主库还存在一个单实例的物理standby只读库和逻辑standby报表库,切换后需要对这两个库进行处理,可以接收新的RAC主库的redo。此方案和使用RMAN全备进行异机恢复的迁移方式对比,优点是停机时间短,并且迁移后无需重新配置原来的两个单实例备库。
一、 环境信息
当前一主多备架构数据库环境信息如下:

二、 一主多备架构下主备切换步骤
需要把当前RAC主库切换成备库,把RAC备库切换成新的RAC主库,其余两个单实例备库指向新的RAC主库,具体操作步骤如下:
2.1 检查当前RAC主库是否可以被切换成备用角色
[oracle@ngpdb01 trace]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Fri Aug 7 09:50:57 2020
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
--------------------
SESSIONS ACTIVE
TO STANDBY或者SESSIONS ACTIVE状态下,主库可以切换成备库角色
2.2 原RAC主库启动switchover
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY WITH SESSION SHUTDOWN;
Database altered.
2.3 shutdown原RAC主库并且启动到mount状态
[oracle@ngpdb01 trace]$ srvctl stop database -d ngpdb
PRCC-1016 : ngpdb was already stopped
[oracle@ngpdb01 trace]$ srvctl start database -d ngpdb -o mount
2.4 查询switchover目标RAC备库是否准备好切换成为新的主库
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
--------------------
TO PRIMARY
TO PRIMARY或者SESSIONS ACTIVE 状态说明备库已经准备好切换成主库角色
2.5 切换目标RAC物理备库成为主库
SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
Database altered.
2.6 打开新的RAC主库
节点1执行:
[oracle@ngpdb03 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.4.0 Production on Fri Aug 7 10:10:14 2020
Copyright (c) 1982, 2013, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
SQL> select open_mode from v$database;
OPEN_MODE
--------------------
MOUNTED
SQL&g

本文介绍了在Oracle 11g环境中,如何进行一主多备架构下的主备切换,包括RAC主库切换为备库,RAC备库升级为主库,以及确保两个单实例备库与新主库同步的详细步骤和验证方法。
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