查询库状态：
SQL> select name,SWITCHOVER_STATUS,open_mode,PROTECTION_MODE,DATABASE_ROLE
????????? from v$database;

验证archive log是否接收和 applied.
SQL> alter session set nls_datE_format='YYYY-MM-DD HH24:MI:SS';

select SEQUENCE#,DEST_ID,ARCHIVED,APPLIED,DELETED,
STATUS,FIRST_TIME from v$archived_log order by SEQUENCE#;

启动到管理模式:
SQL> shutdown immediate;
SQL> startup nomount
SQL> alter database mount standby database
SQL> recover managed standby database disconnect from session;
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SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

10g以后，采用联机日志的传递传递方式，
SQL> recover managed standby database using current logfile disconnect from session;

启动到只读模式：
SQL> shutdown immediate;
SQL> startup nomount
SQL> alter database mount standby database
SQL> alter databae open read only;

在管理模式恢复到只读模式：
SQL> recover managed standby database cancel;
SQL> alter database open read only

在只读模式可以给数据库添加临时数据文件（在rman备份是没有备份的），想让standby提供只读服务或者切换成主库，最好先增加链式文件
SQL> alter tablespace temp add tempfile 'C:\oracle\product\10.2.0\oradata\dgtest\temp02.dbf' size 100m;

只读模式到管理模式
SQL> recover managed standby database disconnect from session;

在备库进行备份
1.停止应用程序，跳转到 read only模式，同坐backup database命令来备份数据库，这样数据库处于一致性模式
2. 备份完成后，备份控制文件
SQL> ALTER DATABASE BACKUP CONTROLFILE TO 'FILE NAME';

主备切换

正常切换 (switchover)
切换准备: 准备参数文件，平时应该备好，注意参数 fal_server，fal_client

先确认能否转换：
SELECT SWITCHOVER_STATUS FROM V$DATABASE;

主 -> 备
$lsnrclt stop
杀光进程或者重启数据库
SQL> alter database commit to switchover to physical standby with session shutdown;

SQL> shutdown immediate;
SQL> startup nomount pfile ='';
SQL> alter database mount standby database;
SQL> recover managed standby database disconnect;

备 -> 主
SQL> alter database commit to switchover to primary with session shutdown;
SQL> shutdown immediate
SQL> startup pfile =''

如果考虑在主备库来回切换，要保证数据库版本一致，参数compatible一致

失败切换 (Failover)
主服务器不能使用情况下

在备库
SQL> recover managed standby database cancel;

--如果在备用库上有备用库日志文件，参考命令
SQL> alter database recover managed standby database finish; -- [force|wait|nowait] 10g or later
--没有备库日志文件[10gR2之前]
SQL> alter database recover managed standby database finish skip standby logfile;

--切换备库到主库
SQL> alter database commit to switchover to primary;
-- open
SQL> shutdown immediate;
SQL> startup pfile=''

如果还有为传递的归档日志或者主库的联机日志
SQL>alter database register logfile 'c:\...'
SQL>recover standby database;

强行切换（激活）
激活备用服务器，在重启数据库时，备库会resetlog。
SQL>alter system archive log current;
SQL>recover managed standby database cancel;
SQL>alter database activate standby database;
SQL>shutdown immediate;
SQL>startup pfile=''

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apply 主库redolog并强制切换
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
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