Which four are true about the Archive (ARCn) processes?
A)They might be used during instance recovery.
B)They can create archivelogs.
C)They are always used during instance recovery.
D)They archive redo from an active redo log.
E)They are always used during media recovery.
F)They can ship redo automatically to standby databases
G)They might be used during media recovery.
Answer: BDFG
赵：
AC 错，ARCn 的作用是在日志切换发生时把切换后的重做日志文件复制到归档日志文件，与实例恢复没有关系。
E 错，不是一直。只有在数据文件损坏、在线日志文件损坏等情况发生时，才用介质恢复。
F 译：它们可以自动将重做发送到备用数据库。
