七． 一些其他操作

1. 设置新的数据保护模式并重启数据库  --primary数据库操作

当保护模式更改顺序：maximize protection --->  maximize availability ----> maximize performance

当在把dataguard的保护级别按这上面的顺序减低的时候，不需要primary库在mount状态，否则primary 必须在mount 状态。如：

SQL> select protection_mode,protection_level from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE

SQL> alter database set standby database to maximize availability;

SQL> select protection_mode,protection_level from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM AVAILABILITY RESYNCHRONIZATION

SQL> alter system switch logfile;

SQL> select protection_mode,protection_level from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM AVAILABILITY RESYNCHRONIZATION

SQL> shutdown immediate;

SQL> startup

SQL> select protection_mode,protection_level from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM AVAILABILITY RESYNCHRONIZATION

Maximum protection/AVAILABILITY/ PERFORMANCE模式必须满足的条件

SQL> alter system set log_archive_dest_2='SERVICE=stby LGWR SYNC AFFIRM valid_for=(ONLINE_LOGFILES,PRIMARY_ROLES) DB_UNIQUE_NAME=stby' scope=spfile;

SQL> shutdown immediate;

SQL> startup mount;

SQL> alter database set standby database to maximize availability;

SQL> alter database open;

Database altered.

SQL> select protection_mode,protection_level from v$database;

PROTECTION_MODE      PROTECTION_LEVEL

-------------------- --------------------

MAXIMUM AVAILABILITY MAXIMUM AVAILABILITY

alter database set standby database to maximize performance;

提示：maximize后可跟{PROTECTION | AVAILABILITY | PERFORMANCE}，分别对应最大保护，最高可用性及最高性能。

在最大保护模式下，直接关闭备库是不行的，如果在备库上关闭数据库，会有如下提示：

SQL> shutdown immediate

ORA-01154: database busy. Open, close, mount, and dismount not allowed now

在最大保护模式下，备库是不允许关闭的，此时首先关闭主库，然后备库就可以顺利关闭了。

注意：主库的保护模式修改之后，备库的模式也会改变，和主库保持一致。

3. 查看日志归档情况

主库进行日志切换:

SQL>Alter system switch logfile;

select max(sequence#) from v$archived_log;

select max(sequence#) from v$log_history;

select group#,sequence#,archived,status from v$log;

select name,sequence#,applied from v$archived_log;

select sequence#,applied from v$archived_log;

若不同步，

1）看log日志，archive是否有丢失

2）可以在备库做如下操作：

alter database recover managed standby database cancel;

alter database recover managed standby database disconnect from session;