rman backup database force

FORCE

Causes RMAN to ignore backup optimization. In other words, even if CONFIGURE BACKUP OPTIMIZATION is set to ON, RMAN backs up all specified files.

Note: You can also specify this option in the backupSpecOperand clause.

加上FORCE选项，则RMAN忽略调CONFIGURE里的优化功能选项．
比如：你配置了RMAN优化功能为ON，之前对只读表空间作了备份，这时，再备份全库，不加FORCE. 则RMAN不会备份只读表空间，因为之前已经备份过，加上FORCE，则RMAN忽略掉优化功能,作全库备份.

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