17.You configure AUTOBACKUP to ON in an RMAN session. When will RMAN back up the control file?
(Choose all that apply.)
A. When you run an RMAN BACKUP command
B. When you run an RMAN ALLOCATE command
C. When you add or drop a table in the SYSTEM tablespace
D. When you change the physical structure of the database, such as dropping a tablespace
E. When you specify the INCLUDING CONTROLFILE clause
原答案：A
正确答案: ADE
【解析】
此处的atuobackup on 指：CONFIGURE CONTROLFILE AUTOBACKUP ON。
此时有2种情况会触发自动备份控制文件：
You can back up the control file when the database is mounted or open. RMAN uses a snapshot control file to ensure a read-
consistent version. If theCONFIGURE CONTROLFILE AUTOBACKUP command is set to ON (by default it is OFF), then RMAN automatically
backs up the control file and server parameter file after every backup and after database structural changes. The control file
autobackup contains metadata about the previous backup, which is crucial fordisaster recovery
手动备份控制文件：
If the autobackup feature is not set, then you must manually back up the control file in one of the following ways:
Run BACKUP CURRENT CONTROLFILE .
Include a backup of the control file within any backup by using the INCLUDE CURRENT CONTROLFILE option of the BACKUP command.
Back up data file 1, because RMAN automatically includes the control file and server parameter file in backups of data file 1
A、rman执行backup命令；
D、数据库结构发生改变，如：新增或删除表空间操作。11g有控制文件自动延迟备份特性，详细参考：
http://blog.chinaunix.net/uid-22948773-id-3347991.html
E、手动备份控制文件，rman命令下执行备份命令 指定INCLUDING CONTROLFILE条件。