检查磁盘是否正常方法：
grid用户操作
kfod扫描盘，当ASM在mount磁盘组时发生故障，尤其是报错信息与发现磁盘相关时，尽快执行一次kfod能得到非常有参考价值的诊断结果。
kfed读盘
dd 查看是否有读权限
[grid@lxtrac03 ~]$ kfod disks=all status=ture asm_diskstring='/dev/mapper/*'
--------------------------------------------------------------------------------
Disk Size Header Path User Group
================================================================================
1: 102400 MB MEMBER AFD:DATA01
2: 102400 MB PROVISIONED AFD:DATA02
3: 15360 MB MEMBER AFD:NEWOCR01
4: 15360 MB MEMBER AFD:NEWOCR02
5: 15360 MB MEMBER AFD:NEWOCR03
6: 15360 MB MEMBER AFD:OCR01
7: 15360 MB MEMBER AFD:OCR02
8: 15360 MB MEMBER AFD:OCR03
--------------------------------------------------------------------------------
ORACLE_SID ORACLE_HOME
================================================================================
[grid@lxtrac03 ~]$
[grid@lenovotest2 ~]$ strace -f -o /tmp/kfod.strace kfod disks=all asm_diskstring='/dev/mapper/*'
[grid@lenovotest2 ~]$ more /tmp/kfod.strace|grep /dev
查看磁盘的状态
[grid@lxtrac03 ~]$ kfed read AFD:OCR01 |grep hdrsts
kfdhdb.hdrsts: 3 ; 0x027: KFDHDR_MEMBER
[grid@lxtrac03 ~]$
dd拷贝数据，确认grid对磁盘有读的权限
[grid@lxtrac03 disks]$ dd if=/dev/sdd5 of=/tmp/data.txt bs=1024k count=1
1+0 records in
1+0 records out
1048576 bytes (1.0 MB) copied, 0.0322265 s, 32.5 MB/s
[grid@lxtrac03 disks]$