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. ALTER DISKGROUP DATA1 DROP DISK DATA1_0001;
CREATE DISKGROUP DATA2 NORMAL REDUNDANCY FAILGROUP DATA1A DISK ,,
/dev/raw/raw3 FAILGROUP DATA1B DISK ,,/dev/raw/raw4;
ALTER DISKGROUP DATA1 UNDROP DISKS;
B. ALTER DISKGROUP DATA1 DROP DISK DATA1_0001;
CREATE DISKGROUP DATA2 HIGH REDUNDANCY FAILGROUP DATA1A DISK ‘/dev/raw/raw3‘
FAILGROUP DATA1B DISK ‘/dev/raw/raw4;‘ALTER DISKGROUP DATA1 UNDROP DISKS;
C. ALTER DISKGROUP DATA1 DROP DISK DATA1_0001;CREATE DISKGROUP DATA2 NORMAL
REDUNDANCY FAILGROUP DATA1A DISK ‘/dev/raw/raw3‘ FAILGROUP DATA1B DISK ‘/dev/raw/raw4‘;
ALTER DISKGROUP DATA1 UNDROP DATA1_0001;
D. ALTER DISKGROUP DATA1 DROP DISK DATA1_0001 ADD DISK GROUP DATA2 NORMAL
REDUNDANCY FAILGROUP DATA1A DISK ‘/dev/raw/raw3‘ FAILGROUP DATA1B DISK ‘/dev/raw/raw4‘;
ALTER DISKGROUP DATA1 UNDROP DISKS;
Note that the UNDROP operation will cancel a drop operation in progress but cannot
reverse a drop operation that has already completed.For HIGH REDUNDANCY,at least three
failure groups must be specified.While you can combine a drop and add operation into one
command,the command can reference only one disk group.
原文：http://www.cnblogs.com/Babylon/p/7800290.html