RMAN > report need backup redundancy 2 database;

报告备份文件低于2份的所有数据文件；

Use RMAN can recover completely database when partial data file is been damage on database based on RMAN incremental backup.

在实现基于RMAN增量备份的基础上，当数据库部分数据发生损坏时，使用RMAN工具可以实现数据库完全恢复；

Each database to be backed up by RMAN must be registered!

又在网上查找原因，原来还需要注册数据库！！

RMAN queries the metadata and does not actually read the backup files.

RMAN只是查询了原数据，实际上并没有读取备份文件。

Online logs CANNOT be backed up using RMAN; they must be archived first.

联机日志不能用RMAN来备份，必须先将其归档。

Large Pool — Memory allocated for use by RMAN for backup and recovery.

大型池 ——分配给RMAN用于备份和恢复的内存。

The RMAN backup and recovery environment is preconfigured for each target database.

对每个目标数据库来说RMAN的备份恢复环境都要预先配置。

Use the RMAN utility to back up the database while the database is offline or online.

在数据库离线或在线的情况下，使用 RMAN 实用程序备份数据库。

The RMAN environment consists of the utilities and databases that play a role in backing up your data.

RMAN的环境由各种工具和数据库组成，在备份数据的时候扮演了重要的角色。

The configuration is persistent and applies to all subsequent operations on this target database, even if you exit and restart RMAN.

在目标数据库上做的后续操作该配置都将永久有效，即使你退出或者重启RMAN。