[Oracle] DataGuard switchover

Oracle DataGuard switchover

2013/07/11

Tag.Data Guard,primary,standby,switchover

切换前primary site和standby site状态检查

• Primary site.

  1. 确认primary site和standby site没有出现日志裂隙(log file gap)

      SQL> select status,gap_status from v$archive_dest_status where dest_id=2;
     
      STATUS    GAP_STATUS
      --------- ------------------------
      VALID     NO GAP
     

  2. 确认primary可以转换成standby角色

      SQL> select switchover_status from v$database;
     
      SWITCHOVER_STATUS
      --------------------
      TO STANDBY
     

     --注意:

     switchover_status应为to standby/session active/not allowed
     
     a. to standby 表示可以转换
     
     b. session active 表示还有活动的session,通过v$session确认活动会话
     
     c. not allowed 表示不能转换

  3. 查看当前会话数

      SQL> select count(*) from v$session where username is not null;
     
        COUNT(*)
      ----------
               1
     

  4. 查看primary其他信息

      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ WRITE           MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO STANDBY
     

• Standby site.

  1. 查看standby site端switchover状态

      SQL> select switchover_status,database_role from v$database;
     
      SWITCHOVER_STATUS    DATABASE_ROLE
      -------------------- ----------------
      NOT ALLOWED          PHYSICAL STANDBY
     

  2. 确认standby site没有日志应用延迟

      SQL> select delay_mins from v$archive_dest where dest_id=2;
     
      DELAY_MINS
      ----------
               0
     

     如果有延迟设置.在standby site禁用延迟

      alter database recover managed standby database nodelay;
     

  3. 查看standby其他信息

      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ ONLY WITH APPLY MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  NOT ALLOWED
     

• 切换

  --注意:

  现将primary将为standby,再将standby升为priamry

  1. primary切到standby

      SQL> select database_role from v$database;
     
      DATABASE_ROLE
      ----------------
      PRIMARY
     
      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ WRITE           MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO STANDBY
     
      SQL> alter database commit to switchover to physical standby;
     
      Database altered.
     

     ========================================

      SQL> shutdown immediate;
      ORA-01092: ORACLE instance terminated. Disconnection forced
      SQL> shutdown immediate;
      ORA-24324: service handle not initialized
      ORA-01041: internal error. hostdef extension doesn't exist
      SQL> select open_mode from v$database;
      ERROR:
      ORA-03114: not connected to ORACLE
     
      SQL> exit
      Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
      With the Partitioning, OLAP, Data Mining and Real Application Testing options
     

     ========================================

      [oracle@TENCENT64 /u]$ sqlplus / as sysdba
     
      SQL*Plus: Release 11.2.0.2.0 Production on Thu Jul 11 19:57:50 2013
     
      Copyright (c) 1982, 2010, Oracle.  All rights reserved.
     
      Connected to an idle instance.
      SQL>
     

     =========================================

      SQL> startup nomount;
      ORACLE instance started.
     
      Total System Global Area 1603411968 bytes
      Fixed Size                  2226912 bytes
      Variable Size             503317792 bytes
      Database Buffers         1090519040 bytes
      Redo Buffers                7348224 bytes
     
      SQL> alter database mount standby database;
     
      Database altered.
     
      SQL> alter database recover managed standby database disconnect from session;
     
      Database altered.
     
      SQL> select database_role from v$database;
     
      DATABASE_ROLE
      ----------------
      PHYSICAL STANDBY
     
      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      MOUNTED              MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO PRIMARY
     

     观察alert日志可以发现primary已经成功切换成Physical Standby database

      Thu Jul 11 19:58:56 2013
      Successful mount of redo thread 1, with mount id 3458571643
      Physical Standby Database mounted.
     

  2. standby切到primary

      SQL> select database_role from v$database;
     
      DATABASE_ROLE
      ----------------
      PHYSICAL STANDBY
     
      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ ONLY WITH APPLY MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO PRIMARY
     
      SQL> alter database commit to switchover to primary;
     
      Database altered.
     
      SQL> shutdown immediate;
      ORA-01109: database not open
     
      Database dismounted.
      ORACLE instance shut down.
     
      SQL> startup;
      ORACLE instance started.
     
      Total System Global Area 1603411968 bytes
      Fixed Size                  2226912 bytes
      Variable Size             486540576 bytes
      Database Buffers         1107296256 bytes
      Redo Buffers                7348224 bytes
      Database mounted.
      Database opened.
     
      SQL> select database_role from v$database;
     
      DATABASE_ROLE
      ----------------
      PRIMARY
     
      SQL> select open_mode,protection_mode,protection_level,switchover_status from v$database;
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ WRITE           MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  RESOLVABLE GAP
     
      SQL> /
     
      OPEN_MODE            PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS
      -------------------- -------------------- -------------------- --------------------
      READ WRITE           MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO STANDBY
     

     观察alert日志可以发现standby已经成功切换成Primary

      Standby became primary SCN: 1362898
      Switchover: Complete - Database mounted as primary
      Completed: alter database commit to switchover to primary
     

  最后,修改primary site和standby site的tnsnames.ora

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