data 磁盘组为normal 模式：
故障现象：
data 磁盘组一块磁盘显示 MISSING
SQL> @chk
DG_NAME DG_STATE TYPE DSK_NO DSK_NAME PATH MOUNT_S FAILGROUP STATE
--------------- ---------- ------ ---------- ---------- -------------------------------------------------- ------- -------------------- --------
DATA MOUNTED NORMAL 0 DATA_0000 /dev/oracleasm/disks/VOT3 CACHED ZC NORMAL
DATA MOUNTED NORMAL 1 _DROPPED_0 MISSING B FORCING
001_DATA
DATA MOUNTED NORMAL 2 DATA_0002 /dev/oracleasm/disks/VOT1 CACHED A NORMAL
MGMT MOUNTED EXTERN 0 MGMT_0000 /dev/oracleasm/disks/DATA01 CACHED MGMT_0000 NORMAL
DISK_NUMBER NAME PATH HEADER_STATUS OS_MB TOTAL_MB FREE_MB REPAIR_TIMER V FAILGRO
----------- ---------- -------------------------------------------------- -------------------- ---------- ---------- ---------- ------------ - -------
0 /dev/oracleasm/disks/VOT2 MEMBER 2048 0 0 0 Y REGULAR
1 _DROPPED_0 UNKNOWN 0 2048 1704 0 N REGULAR
001_DATA
0 MGMT_0000 /dev/oracleasm/disks/DATA01 MEMBER 51199 51196 17388 0 N REGULAR
0 DATA_0000 /dev/oracleasm/disks/VOT3 MEMBER 2048 2048 2004 0 Y QUORUM
2 DATA_0002 /dev/oracleasm/disks/VOT1 MEMBER 2048 2048 1704 0 Y REGULAR
GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY V
------------ ---------- ------------------------------------------------------------ ------------------------------------------------------------ -
2 MGMT 12.2.0.1.0 10.1.0.0.0 N
1 DATA 12.2.0.1.0 10.1.0.0.0 Y
SQL>解决方法：
01.重新添加磁盘到failgroup B
SQL> ALTER DISKGROUP data add failgroup b DISK '/dev/oracleasm/disks/VOT2' force;
Diskgroup altered.
SQL> @chk
DG_NAME DG_STATE TYPE DSK_NO DSK_NAME PATH MOUNT_S FAILGROUP STATE
--------------- ---------- ------ ---------- ---------- -------------------------------------------------- ------- -------------------- --------
DATA MOUNTED NORMAL 0 DATA_0000 /dev/oracleasm/disks/VOT3 CACHED ZC NORMAL
DATA MOUNTED NORMAL 1 _DROPPED_0 MISSING B FORCING
001_DATA
DATA MOUNTED NORMAL 2 DATA_0002 /dev/oracleasm/disks/VOT1 CACHED A NORMAL
DATA MOUNTED NORMAL 3 DATA_0003 /dev/oracleasm/disks/VOT2 CACHED B NORMAL
MGMT MOUNTED EXTERN 0 MGMT_0000 /dev/oracleasm/disks/DATA01 CACHED MGMT_0000 NORMAL
DISK_NUMBER NAME PATH HEADER_STATUS OS_MB TOTAL_MB FREE_MB REPAIR_TIMER V FAILGRO
----------- ---------- -------------------------------------------------- -------------------- ---------- ---------- ---------- ------------ - -------
1 _DROPPED_0 UNKNOWN 0 2048 1724 0 N REGULAR
001_DATA
0 MGMT_0000 /dev/oracleasm/disks/DATA01 MEMBER 51199 51196 17388 0 N REGULAR
0 DATA_0000 /dev/oracleasm/disks/VOT3 MEMBER 2048 2048 2004 0 Y QUORUM
2 DATA_0002 /dev/oracleasm/disks/VOT1 MEMBER 2048 2048 1704 0 Y REGULAR
3 DATA_0003 /dev/oracleasm/disks/VOT2 MEMBER 2048 2048 1984 0 Y REGULAR
GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY V
------------ ---------- ------------------------------------------------------------ ------------------------------------------------------------ -
2 MGMT 12.2.0.1.0 10.1.0.0.0 N
1 DATA 12.2.0.1.0 10.1.0.0.0 Y
02.平衡完成之后，检查磁盘组状态
SQL> @chk
DG_NAME DG_STATE TYPE DSK_NO DSK_NAME PATH MOUNT_S FAILGROUP STATE
--------------- ---------- ------ ---------- ---------- -------------------------------------------------- ------- -------------------- --------
DATA MOUNTED NORMAL 0 DATA_0000 /dev/oracleasm/disks/VOT3 CACHED ZC NORMAL
DATA MOUNTED NORMAL 2 DATA_0002 /dev/oracleasm/disks/VOT1 CACHED A NORMAL
DATA MOUNTED NORMAL 3 DATA_0003 /dev/oracleasm/disks/VOT2 CACHED B NORMAL
MGMT MOUNTED EXTERN 0 MGMT_0000 /dev/oracleasm/disks/DATA01 CACHED MGMT_0000 NORMAL
DISK_NUMBER NAME PATH HEADER_STATUS OS_MB TOTAL_MB FREE_MB REPAIR_TIMER V FAILGRO
----------- ---------- -------------------------------------------------- -------------------- ---------- ---------- ---------- ------------ - -------
0 MGMT_0000 /dev/oracleasm/disks/DATA01 MEMBER 51199 51196 17388 0 N REGULAR
0 DATA_0000 /dev/oracleasm/disks/VOT3 MEMBER 2048 2048 2004 0 Y QUORUM
2 DATA_0002 /dev/oracleasm/disks/VOT1 MEMBER 2048 2048 1704 0 Y REGULAR
3 DATA_0003 /dev/oracleasm/disks/VOT2 MEMBER 2048 2048 1704 0 Y REGULAR
GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY V
------------ ---------- ------------------------------------------------------------ ------------------------------------------------------------ -
2 MGMT 12.2.0.1.0 10.1.0.0.0 N
1 DATA 12.2.0.1.0 10.1.0.0.0 Y
SQL> 03,避免该问题再次发生！
SQL> ALTER DISKGROUP data SET ATTRIBUTE 'compatible.rdbms' = '11.2';
Diskgroup altered.
SQL> @chk
DG_NAME DG_STATE TYPE DSK_NO DSK_NAME PATH MOUNT_S FAILGROUP STATE
--------------- ---------- ------ ---------- ---------- -------------------------------------------------- ------- -------------------- --------
DATA MOUNTED NORMAL 0 DATA_0000 /dev/oracleasm/disks/VOT3 CACHED ZC NORMAL
DATA MOUNTED NORMAL 2 DATA_0002 /dev/oracleasm/disks/VOT1 CACHED A NORMAL
DATA MOUNTED NORMAL 3 DATA_0003 /dev/oracleasm/disks/VOT2 CACHED B NORMAL
MGMT MOUNTED EXTERN 0 MGMT_0000 /dev/oracleasm/disks/DATA01 CACHED MGMT_0000 NORMAL
DISK_NUMBER NAME PATH HEADER_STATUS OS_MB TOTAL_MB FREE_MB REPAIR_TIMER V FAILGRO
----------- ---------- -------------------------------------------------- -------------------- ---------- ---------- ---------- ------------ - -------
0 MGMT_0000 /dev/oracleasm/disks/DATA01 MEMBER 51199 51196 17388 0 N REGULAR
0 DATA_0000 /dev/oracleasm/disks/VOT3 MEMBER 2048 2048 2004 0 Y QUORUM
2 DATA_0002 /dev/oracleasm/disks/VOT1 MEMBER 2048 2048 1704 0 Y REGULAR
3 DATA_0003 /dev/oracleasm/disks/VOT2 MEMBER 2048 2048 1704 0 Y REGULAR
GROUP_NUMBER NAME COMPATIBILITY DATABASE_COMPATIBILITY V
------------ ---------- ------------------------------------------------------------ ------------------------------------------------------------ -
2 MGMT 12.2.0.1.0 10.1.0.0.0 N
1 DATA 12.2.0.1.0 11.2.0.0.0 Y
SQL> 