Oracle 11g DG Broker开启fast-start failover自动故障切换

一.首先保证主从数据库的闪回数据库功能以及强制归档都打开，如下保证都为yes

SQL> select flashback_on,force_logging from v$database;

FLASHBACK_ON      FOR

------------------ ---

NO                NO

1.1开启闪回数据库

SQL> ALTER SYSTEM SET db_recovery_file_dest_size=3g SCOPE=BOTH;

System altered.

SQL> alter system set  db_recovery_file_dest='/data/u01/app/Oracle/fast_recovery_area';

System altered.

SQL> alter database flashback on;

Database altered.

1.2开启强制归档

SQL>  alter database force logging;

Database altered.

SQL> select flashback_on,force_logging from v$database;

FLASHBACK_ON      FOR

------------------ ---

YES                YES

二：开启fast-start failover

2.1：开启 fast-start failover

[oracle@beijing-fuli-Hadoop-02 ~]$ dgmgrl  sys/  oracle@db2 

DGMGRL for Linux: Version 11.2.0.4.0 - 64bit Production

Copyright (c) 2000, 2009, Oracle. All rights reserved.

Welcome to DGMGRL, type "help" for information.

Connected.

DGMGRL>  enable fast_start failover;

Enabled.

2.2.查看配置状态，发现警告，因为没有启动observer而告警！

DGMGRL> show configuration

Configuration - dbha_c

Protection Mode: MaxPerformance

Databases:

db2 - Primary database

Warning: ORA-16819: fast-start failover observer not started

db1 - (*) Physical standby database

Warning: ORA-16819: fast-start failover observer not started

Fast-Start Failover: ENABLED

Configuration Status:

WARNING

2.3开启 启动观察器（observer）：

DGMGRL> show configuration

Configuration - dbha_c

Protection Mode: MaxPerformance

Databases:

db2 - Primary database

db1 - (*) Physical standby database

Fast-Start Failover: ENABLED

Configuration Status:

SUCCESS

由于observer的启动会一直占用session 窗口的，所以建议写成脚本挂后台

这里我们在备库上创建脚本，具体如下

创建一个名叫observer.sql的脚本，把下面的命令放进去，然后执行该脚本即可。

nohup dgmgrl  sys/oracle@db2 "start observer">>observer.log 2>&1 &

三：验证自动切换：

db2主库：

SQL> select  DATABASE_ROLE,OPEN_MODE from  v$database;

DATABASE_ROLE    OPEN_MODE

---------------- --------------------

PRIMARY          READ WRITE

db1为standby

SQL> select  DATABASE_ROLE,OPEN_MODE from  v$database;

DATABASE_ROLE    OPEN_MODE

---------------- --------------------

PHYSICAL STANDBY READ ONLY WITH APPLY

db2主库模拟异常关闭

SQL> shu abort

ORACLE instance shut down.

再次查看db1的状态：

SQL> select  DATABASE_ROLE,OPEN_MODE from  v$database;

DATABASE_ROLE    OPEN_MODE

---------------- --------------------

PRIMARY          READ WRITE