10g datagurad的一次switchover

查询主库的状态：

SQL>select switchover_status from v$database;

SWITCHOVER_STATUS

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

SESSIONSACTIVE

更换主库的角色：

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

Database altered.

这时alter_log有以下信息，说明自动建立了standby log：

standbyredo logfiles that match the primary database:

ALTERDATABASE ADD STANDBY LOGFILE 'srl1.f' SIZE 52428800;

ALTERDATABASE ADD STANDBY LOGFILE 'srl2.f' SIZE 52428800;

ALTERDATABASE ADD STANDBY LOGFILE 'srl3.f' SIZE 52428800;

ALTER DATABASE ADD STANDBY LOGFILE 'srl4.f' SIZE 52428800;

备库的switchover_status 的状态从not allowed改成了to primary:

SQL>select switchover_status from v$database;

SWITCHOVER_STATUS

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

NOTALLOWED

SQL>select switchover_status from v$database;

SWITCHOVER_STATUS

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

TOPRIMARY

将备库改成主库：

SQL>ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

Database altered.

SQL>select switchover_status from v$database;

SWITCHOVER_STATUS

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

TO STANDBY

SQL> select DATABASE_ROLE fromv$database;



DATABASE_ROLE

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

PRIMARY

测试一下，原来的主库已开始接收Log了。

SQL> alter system switchlogfile;

System altered.

新主库的alert_log:

RFS[4]: Identified database type as'physical standby'

Thu Aug  1 13:03:47 2013

Primary database is in MAXIMUMPERFORMANCE mode

RFS[2]: Successfully opened standbylog 5: '/u01/app/oracle/oradata/orcl/redo05.log'

再做一次switchover，恢复到最初的状态：

在主库执行：

SQL> select switchover_statusfrom v$database;

SWITCHOVER_STATUS

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

SESSIONS ACTIVE

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

Database altered.

在备库执行：

SQL> select switchover_statusfrom v$database;

SWITCHOVER_STATUS

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

NOT ALLOWED

SQL>  select switchover_status from v$database;

SWITCHOVER_STATUS

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

TO PRIMARY

SQL> ALTER DATABASE COMMIT TOSWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

Database altered.

SQL> select switchover_statusfrom v$database;

SWITCHOVER_STATUS

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

TO STANDBY

分别重启主重库后：

SQL> startup mount

ORACLE instance started.

Total System Global Area  281018368 bytes

Fixed Size                  1218944 bytes

Variable Size             100664960 bytes

Database Buffers          171966464 bytes

Redo Buffers                7168000 bytes

Database mounted.

SQL> select  PROTECTION_MODE,PROTECTION_LEVEL  from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

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

MAXIMUM AVAILABILITY MAXIMUM AVAILABILITY

SQL> recover managed standbydatabase disconnect from session;

Media recovery complete.

主库切换一次logfile;

SQL>  alter system switch logfile;

System altered.

备库的日志：

Thu Aug  1 14:19:44 2013

Primary database is in MAXIMUMAVAILABILITY mode

Standby controlfile consistent withprimary

RFS[2]: Successfully opened standbylog 5: '/u01/app/oracle/oradata/orcl/redo05.log'

Thu Aug  1 14:19:48 2013

Media Recovery Log/u01/app/oracle/oradata/orcl/archivelog/1_72_793805797.dbf

Media Recovery Waiting for thread 1sequence 73 (in transit)

成功！