053-87

You want to perform an RMAN backup of database as a copy. Which two factors will you consider while performing the backup operation? (Choose two).
A. The backup as copy can only be taken to disk
B. The backup as copy can only be taken to tape
C. Backup can be performed only when the instance is shutdown
D. Backup will constitute all used and unused blocks in the database

constitute(构成)
backup as copy 不是以 RMAN 指定的格式存储，其和系统级别拷贝命令相同，RMAN 也支持使用这些操作系统进行的拷贝。
于备份集不同（会使用 unused 块压缩），镜像拷贝是 bit-to-bit 的方式，所以会备份所有的块。由于镜像拷贝只能写到磁盘上，所以磁带设备只能使用备份集。
镜像拷贝可以在 mount 下进行，所以 C 错。