How can you reverse the effects of an ALTER DISKGROUP ... DROP DISK command if it has already completed？（）  

单项选择题Whichtypeofdatabasefileisspreadacrossalldisksinadiskgroup？（）

A. All types of files are spread across all disks in the disk group.
B. Datafiles
C. Redo log files
D. Archived redo log files
E. Control files

单项选择题On the development database rac0， there are six raw devices：  dev raw raw1 through  dev raw raw6.  dev raw raw1 and  dev raw raw2 are 8GB each， and the rest are 6GB each. An existing disk group +DATA1， of NORMAL REDUNDANCY， uses  dev raw raw1 and  dev raw raw2.  Which series of the following commands will drop one of the failure groups for +DATA1， create a new disk group +DATA2 using two of the remaining four raw devices， and then cancel the drop operation from +DATA1？ （）

A.A
B.B
C.C
D.D

单项选择题Whichbackgroundprocesscoordinatestherebalanceactivityfordiskgroups？（）

A. ORBn
B. OSMB
C. RBAL
D. ASMn

单项选择题To reference existing ASM files， you need to use a fully qualified ASM filename. Your development database has a disk group named DG2A， the database name is DEV19， and the ASM file that you want to reference is a datafile for the USERS02 tablespace.  Which of the following is a valid ASM filename for this ASM file？（）

A. dev19/+DG2A/datafile/users02.701.2
B. +DG2A/dev19/datafile/users02.701.2
C. +DG2A/dev19/users02/datafile.701.2
D. +DG2A·701.2
E. +DG2A/datafile/dev19.users.02.701.2

单项选择题HowcanyoureversetheeffectsofanALTERDISKGROUP...DROPDISKcommandifithasnotyetcompleted？（）

A. Issue the ALTER DISKGROUP ... ADD DISK command.
B. Issue the ALTER DISKGROUP ... UNDROP DISKS command.
C. Issue the ALTER DISKGROUP ... DROP DISK CANCEL command.
D. Retrieve the disk from the Recycle Bin after the operation completes.