DataGuard角色切換

Step 1   Verify that the primary database can be switched to the standby role.
驗證主庫能夠切換到備用角色。
SELECT SWITCHOVER_STATUS FROM V$DATABASE;
idle>:wq

SWITCHOVER_STATUS
---------------------
 

TO STANDBY

Step 2   Initiate the switchover on the primary database.
在主庫上面開始切換
alter database commit to switchover to physical standby with session shutdown ;

Step 3   Shut down and then mount the former primary database.
關(guān)閉并且mount上從前的主庫。

shutdown abort;
startup mount ;

Step 4   Verify that the switchover target is ready to be switched to the primary role.
驗證轉(zhuǎn)換目標已經(jīng)準備好轉(zhuǎn)換為主庫角色
SWITCHOVER_STATUS
--------------------
SWITCHOVER LATENT

這里查詢出來的值不為TO_PRIMARY即有點問題。
執(zhí)行下一步的時候可能會出現(xiàn)問題。

Step 5   Switch the target physical standby database role to the primary role.
轉(zhuǎn)換目標邏輯備用庫角色為主庫角色。

sys@DEX>  ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;
 ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN
*
ERROR at line 1:
ORA-16139: media recovery required

這里提示需要介質(zhì)恢復。

sys@DEX> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

Database altered.

sys@DEX> SELECT SWITCHOVER_STATUS FROM V$DATABASE;

SWITCHOVER_STATUS
--------------------
TO PRIMARY

sys@DEX> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

Database altered.

Step 6   Open the new primary database.
打開新的主庫
sys@DEX> ALTER DATABASE OPEN;

Database altered.

Step 7 Verify the switch role .
驗證角色轉(zhuǎn)換

主庫執(zhí)行
sys@DEX> alter system switch logfile ;

System altered.

sys@DEX> select sequence# from v$log ;

 SEQUENCE#
----------
        40
        41
        42

sys@DEX>

standby庫執(zhí)行

sys@DEX> select sequence# from v$log ;

 SEQUENCE#
----------
        40
        42
        41

sys@DEX>

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