生产库DG的切换演练

1、单实例到单实例的切换先将主库切换成备库，然后将原主库启动到物理库的状态SQL> select switchover_status from v$database;SWITCHOVER_STATUS--------------------TO STANDBYSQL> Alter database commit to switchover to physical standby with session shutdown;Database altered.SQL> shut immediateORA-01507: database not mountedORACLE instance shut down.SQL> startup nomount;ORACLE instance started.Total System Global Area  304807936 bytesFixed Size                  2212856 bytesVariable Size             176163848 bytesDatabase Buffers          121634816 bytesRedo Buffers                4796416 bytesSQL> alter database mount standby database;Database altered.SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION;Database altered.然后将备库切换成主库SQL> select switchover_status from v$database;SWITCHOVER_STATUS--------------------TO PRIMARYSQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY; Database altered.SQL> ALTER DATABASE open; Database altered.RAC到单实例的切换现有RAC(12C)到单实例的物理DATAGUARD，需要SWITCHOVER主库到单实例上 ，使原来的RAC成为备库，单实例备库成为主库.   在rac和单实例备库上检查DG的相关参数，确认无误.在RAC上，手动实现switch logfile,然后检查备库是已经应用了相用的logfile,以确保事务完全在备库上应用。 SQL> alter system switch logfile;System altered.SQL> archive log list;Database log mode              Archive ModeAutomatic archival             EnabledArchive destination            /u01/app/oracle/product/12.1.0.0/db_1/dbs/archOldest online log sequence     69Next log sequence to archive   70Current log sequence           70SQL> select database_role from v$database;DATABASE_ROLE----------------PRIMARY DG备库上检查SQL> select database_role from v$database;DATABASE_ROLE----------------PHYSICAL STANDBYSQL> select process,client_process,thread#,sequence# from v$managed_standby;PROCESS   CLIENT_P    THREAD#  SEQUENCE#--------- -------- ---------- ----------ARCH      ARCH              1         68ARCH      ARCH              1         64ARCH      ARCH              0          0ARCH      ARCH              1         69RFS       UNKNOWN           0          0RFS       ARCH              0          0RFS       LGWR              2         30RFS       UNKNOWN           0          0RFS       LGWR              1         70RFS       ARCH              0          0RFS       UNKNOWN           0          0PROCESS   CLIENT_P    THREAD#  SEQUENCE#--------- -------- ---------- ----------RFS       UNKNOWN           0          0MRP0      N/A               1         7013 rows selected.在rac主库上执行SQL> alter database commit to switchover to physical standby;Database altered.SQL> select database_role from v$database;DATABASE_ROLE----------------PHYSICAL STANDBY在dg备库提升为主库.SQL> alter database commit to switchover to primary;Database altered.SQL> select database_role from v$database;DATABASE_ROLE----------------PRIMARY打开单实例数据库SQL> alter database open;Database altered.在11.2的版本中在SWITCHOVER时，不需要再更改cluster_database参数重启数据库了，这一点比原来方便很多.在rac节点上启动日志应用.SQL> alter database recover managed standby database disconnect from session;Database altered.SQL> select open_mode from v$database;OPEN_MODE--------------------READ ONLY WITH APPLY             --default已经使用active dataguard了.在单实例主库上手动切换日志，检查在rac备库上应用情况，确认DATAGUARD工作正常.