8.3.5 Adding or Dropping Online Redo Log Files
8.3.5 添加或删除现在重做日志文件
Changing the size and number of the online redo log files is sometimes done to tune the database. You can add or drop online redo log file groups or members to the primary database without affecting the standby database. Similarly, you can drop log file groups or members from the primary database without affecting your standby database. However, these changes do affect the performance of the standby database after switchover.
改变在线重做日志文件大小和数量有时是优化数据库。你可以在主库添加或删除在线重做日志组或者日志成员而不影响备库。同样的，你可以在主库删除日志文件组或成员而不影响你的备库。但是，这边变化在普通切换后会影响备库的性能。
Caution:
注意：
Whenever you add an online redo log file to the primary database, you should add corresponding online and standby redo log files to the standby database.
无论何时，你在主库添加在线重做日志文件，你应该在备库添加相应的在线重做日志和备用重做日志文件。
For example, if the primary database has 10 online redo log files and the standby database has 2, and then you switch over to the standby database so that it functions as the new primary database, the new primary database is forced to archive more frequently than the original primary database.
例如，如果主库有10个在线重做日志，备库有2个，那么你切换到备库时，变为主库，新的主库比原来的主库会强制频繁的归档。
Consequently, when you add or drop an online redo log file at the primary site, it is important that you synchronize the changes in the standby database by following these steps:
因此，当你在主库添加或者删除在线重做日志时，按照如下步骤将这些变化同步到备库是很重要的，
1.
If Redo Apply is running, you must cancel Redo Apply before you can change the log files.
1.如果重做应用正在运行，你必须在你改变日志文件钱取消重做应用。
2.
If the STANDBY_FILE_MANAGEMENT initialization parameter is set to AUTO, change the value to MANUAL.
如果STANDBY_FILE_MANAGEMENT初始化参数设置为AUTO,将它改变为MANUAL。
3.
Add or drop an online redo log file:
3.添加或删除在线重做日志文件：
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To add an online redo log file, use a SQL statement such as this:
添加在线重做日志文件，使用如下SQL语句：
SQL> ALTER DATABASE ADD LOGFILE '/disk1/Oracle/oradata/payroll/prmy3.log' SIZE 100M;
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To drop an online redo log file, use a SQL statement such as this:
删除在线重做日志文件，使用如下SQL语句：
SQL> ALTER DATABASE DROP LOGFILE '/disk1/oracle/oradata/payroll/prmy3.log';
4.
Repeat the statement you used in Step 3 on each standby database.
在每个备库上重复操作步骤3。
5.
Restore the STANDBY_FILE_MANAGEMENT initialization parameter and the Redo Apply options to their original states.
还原STANDBY_FILE_MANAGEMENT初始化参数为AUTO，然后重做应用还原为原来的状态。
相关参考:
Oracle Data Guard 重要配置参数
基于同一主机配置 Oracle 11g Data Guard
探索Oracle之11g DataGuard
Oracle Data Guard （RAC+DG) 归档删除策略及脚本
Oracle Data Guard 的角色转换
Oracle Data Guard的日志FAL gap问题
Oracle 11g Data Guard Error 16143 Heartbeat failed to connect to standby 处理方法