在主机上挂载 USB 设备后我们查看系统当前磁盘设备：

1. [root@FCoE ~]# fdisk -l

2.

3. Disk /dev/sda: 43.0 GB, 42991616000 bytes

4. 255 heads, 63 sectors/track, 5226 cylinders

5. Units = cylinders of 16065 * 512 = 8225280 bytes

6. Sector size (logical/physical): 512 bytes / 512 bytes

7. I/O size (minimum/optimal): 512 bytes / 512 bytes

8. Disk identifier: 0x00032735

9.

10.   Device Boot      Start         End      Blocks   Id  System

11. /dev/sda1   *           1          17      131072   83  Linux

12. Partition 1 does not end on cylinder boundary.

13. /dev/sda2              17         147     1048576   82  Linux swap / Solaris

14. Partition 2 does not end on cylinder boundary.

15. /dev/sda3             147        5227    40803328   83  Linux

16.

17. Disk /dev/sdb: 2147 MB, 2147483648 bytes

18. 255 heads, 63 sectors/track, 261 cylinders

19. Units = cylinders of 16065 * 512 = 8225280 bytes

20. Sector size (logical/physical): 512 bytes / 512 bytes

21. I/O size (minimum/optimal): 512 bytes / 512 bytes

22. Disk identifier: 0x00000000

23.

24. Disk /dev/sdb doesn't contain a valid partition table

ocp认证在新分区 sdb1 上创建文件系统：

1. [root@FCoE ~]# mkfs.ext3 /dev/sdb1

2. mke2fs 1.41.12 (17-May-2010)

3. Filesystem label=

4. OS type: Linux

5. Block size=4096 (log=2)

6. Fragment size=4096 (log=2)

7. Stride=0 blocks, Stripe width=0 blocks

8. 131072 inodes, 524112 blocks

9. 26205 blocks (5.00%) reserved for the super user

10. First data block=0

11. Maximum filesystem blocks=536870912

12. 16 block groups

13. 32768 blocks per group, 32768 fragments per group

14. 8192 inodes per group

15. Superblock backups stored on blocks:

16.        32768, 98304, 163840, 229376, 294912

17.

18. Writing inode tables: done

19. Creating journal (8192 blocks): done

20. Writing superblocks and filesystem accounting information: done

21.

22. This filesystem will be automatically checked every 24 mounts or

23. 180 days, whichever comes first.  Use tune2fs -c or -i to override.

ocp认证挂载新的文件系统：

1. [root@FCoE ~]# mount /dev/sdb1 /mnt/

ocp认证通常我们通过备份硬盘的 MBR 来备份硬盘分区表：

1. [root@FCoE ~]# dd if=/dev/sda of=/mnt/sda.mbr bs=512 count=1

2. 1+0 records in

3. 1+0 records out

4. 512 bytes (512 B) copied, 0.000777948 s, 658 kB/s

ocp认证现在我们来写零硬盘分区表来实现类似分区表被破坏的结果：

1. [root@FCoE ~]# dd if=/dev/zero of=/dev/sda bs=1 count=64 skip=446 seek=446

2. 64+0 records in

3. 64+0 records out

4. 64 bytes (64 B) copied, 0.00160668 s, 39.8 kB/s

ocp认证查询硬盘 sda 上的分区信息，发现其已不包含任何分区： 1. [root@FCoE ~]# fdisk -l   2.  3. Disk /dev/sda: 43.0 GB, 42991616000 bytes   4. 255 heads, 63 sectors/track, 5226 cylinders   5. Units = cylinders of 16065 * 512 = 8225280 bytes   6. Sector size (logical/physical): 512 bytes / 512 bytes   7. I/O size (minimum/optimal): 512 bytes / 512 bytes   8. Disk identifier: 0x00032735   9.  10.   Device Boot      Start         End      Blocks   Id  System   11.  12. Disk /dev/sdb: 2147 MB, 2147483648 bytes   13. 255 heads, 63 sectors/track, 261 cylinders   14. Units = cylinders of 16065 * 512 = 8225280 bytes   15. Sector size (logical/physical): 512 bytes / 512 bytes   16. I/O size (minimum/optimal): 512 bytes / 512 bytes   17. Disk identifier: 0xcdd48395   18.  19.   Device Boot      Start         End      Blocks   Id  System   20. /dev/sdb1               1         261     2096451   83  Linux  当主机硬盘分区表丢失了之后，再次启动后 GRUB 会因找不到配置文件而进入命令行模式。