dataguard 主備切換總結：
系統版本：
SQL> select * from v$version
2 /
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE 11.2.0.4.0 Production關於主備庫的切換命令
在主庫上
SQL> select switchover_status from v$database
2 /
SWITCHOVER_STATUS
--------------------
FAILED DESTINATION應該是主備庫的監聽沒起來，啓動主備庫的監聽，然後
SQL> select switchover_status from v$database
2 /
SWITCHOVER_STATUS
--------------------
TO STANDBY這說明是可以切換到備庫的
SQL> alter database commit to switchover to physical standby
2 /
Database altered.測試數據庫已經關閉了
SQL> select status from v$instance
2 /
select status from v$instance
*
ERROR at line 1:
ORA-01034: ORACLE not available
Process ID: 2994
Session ID: 191 Serial number: 9查看預警日誌， 因爲在轉爲備庫成功以後，oracle會有一個自我關閉的過程哦~
Switchover: Primary controlfile converted to standby controlfile succesfully.
Switchover: Complete - Database shutdown required
USER (ospid: 2994): terminating the instance
Instance terminated by USER, pid = 2994
Completed: alter database commit to switchover to physical standby
Shutting down instance (abort)
License high water mark = 7
Thu Sep 07 11:11:25 2017
Instance shutdown complete
Thu Sep 07 11:11:44 2017那我們就將數據庫啓動到mount狀態吧
SQL> startup mount;
ORACLE instance started.
Total System Global Area 1060585472 bytes
Fixed Size 2260000 bytes
Variable Size 666895328 bytes
Database Buffers 385875968 bytes
Redo Buffers 5554176 bytes
Database mounted.再到備庫上去做相關的操作：
SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
--------------------
TO PRIMARY
SQL> alter database commit to switchover to primary
2 /
Database altered.
SQL> alter database open
2 /
Database altered.預警日誌：
我們的預警日誌詳細記錄了該過程。在轉換完成以後,oracle 默認會被啓動到mount 狀態
alter database commit to switchover to primary
ALTER DATABASE SWITCHOVER TO PRIMARY (orcl)
Maximum wait for role transition is 15 minutes.
Switchover: Media recovery is still active
Role Change: Canceling MRP - no more redo to apply
Thu Sep 07 11:22:38 2017
MRP0: Background Media Recovery cancelled with status 16037
Errors in file /u01/app/oracle/diag/rdbms/orcl_dg/orcl/trace/orcl_pr00_2428.trc:
ORA-16037: user requested cancel of managed recovery operation
Managed Standby Recovery not using Real Time Apply
Recovery interrupted!
Thu Sep 07 11:22:38 2017
MRP0: Background Media Recovery process shutdown (orcl)
Role Change: Canceled MRP
All dispatchers and shared servers shutdown
CLOSE: killing server sessions.
CLOSE: all sessions shutdown successfully.
Thu Sep 07 11:22:39 2017
SMON: disabling cache recovery
Backup controlfile written to trace file /u01/app/oracle/diag/rdbms/orcl_dg/orcl/trace/orcl_ora_2583.trc
SwitchOver after complete recovery through change 1195464
Online log /u01/app/oracle/oradata/orcl_dg/redo01.log: Thread 1 Group 1 was previously cleared
Online log /u01/app/oracle/oradata/orcl_dg/redo02.log: Thread 1 Group 2 was previously cleared
Online log /u01/app/oracle/oradata/orcl_dg/redo03.log: Thread 1 Group 3 was previously cleared
Standby became primary SCN: 1195462
AUDIT_TRAIL initialization parameter is changed back to its original value as specified in the parameter file.
Switchover: Complete - Database mounted as primary
Completed: alter database commit to switchover to primary此時在原來的主庫上再
alter database open
SQL> alter database recover managed standby database using current logfile disconnect from session
2 /
Database altered.測試一下功能：
在原備庫上：
SQL> show parameter db_unique_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_unique_name string orcl_dg
SQL> conn hdp/123123
Connected.
SQL> desc t
Name Null? Type
----------------------------------------- -------- ----------------------------
ID NUMBER
NAME VARCHAR2(200)
SQL> drop table t
2 /
Table dropped.在原主庫上查看
SQL> conn hdp/123123
Connected.
SQL> desc t
ERROR:
ORA-04043: object t does not exist
SQL> show parameter db_unique_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_unique_name string orcl_prd發現該表也被自動drop掉了
後來在主備重新切換的時候還遇到一個問題，我覺得也很典型
SQL> select switchover_status from v$database
2 /
SWITCHOVER_STATUS
--------------------
NOT ALLOWED
SQL> alter database recover managed standby database disconnect from session;
Database altered.
SQL> select switchover_status from v$database
2 /
SWITCHOVER_STATUS
--------------------
TO PRIMARY記錄下當時alert日誌的 報錯
alter database commit to switchover to primary
ALTER DATABASE SWITCHOVER TO PRIMARY (orcl)
Maximum wait for role transition is 15 minutes.
Database not available for switchover
End-Of-REDO archived log file has not been recovered
Incomplete recovery SCN:0:1196867 archive SCN:0:1218437
Database not available for switchover
End-Of-REDO archived log file has not been recovered
Incomplete recovery SCN:0:1196867 archive SCN:0:1218437
Switchover: Media recovery required - standby not in limbo由於我意味終止了我的虛機：
造成了一個錯誤，在此也記錄一下
In-flux buffer recovery was not started because datafiles were fuzzy beyond in-flux recovery target.
Highest datafile fuzzy SCN: 0.1230813
In-flux buffer recovery target SCN: 0.1218830
Managed Recovery: Not Active posted.
DDE rules only execution for: ORA 1110
----- START Event Driven Actions Dump ----
---- END Event Driven Actions Dump ----
----- START DDE Actions Dump -----
Executing SYNC actions
----- START DDE Action: 'DB_STRUCTURE_INTEGRITY_CHECK' (Async) -----
Successfully dispatched
----- END DDE Action: 'DB_STRUCTURE_INTEGRITY_CHECK' (SUCCESS, 0 csec) -----
Executing ASYNC actions
----- END DDE Actions Dump (total 0 csec) -----
ORA-10458: standby database requires recovery
ORA-01196: file 1 is inconsistent due to a failed media recovery session
ORA-01110: data file 1: '/u01/app/oracle/oradata/orcl_dg/system01.dbf'我將主庫起來以後，再嘗試去備庫 alter database open
就可以正常打開了。 DBA在日常工作的學習中，尤其在自己的本機環境，不斷地試錯，不斷地總結經驗！這樣纔會在真正的真實環境中做到心中有數! 且正式環境正式上線後，我們其實很少真正願意去有大的動作了。 平時一直好好的，不要一場不必要的大手術以後，反而真正的動了元氣就不好了。