情况是这样的，开始创建虚拟机的时候硬盘设置太小了，只有10g，我现在通过vbox的设置给这个linux（centos6.6）虚拟机添加了一块硬盘。
下面的操作就是怎么把硬盘挂载到系统中。
通过 fdisk查看现在物理磁盘的信息（这个要用root权限才行）
以下操作均是root权限。
[root@orangleliu ~]# fdisk -l
...
Disk /dev/sdb: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
...写分区表
下面是个交互是过程，每次输入之后根据提示，在进行输入
[root@orangleliu ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xa4378777.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-3916, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-3916, default 3916):
Using default value 3916
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.操作完之后我们再来看磁盘信息
# fdisk -l
...
Disk /dev/sdb: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa4378777
Device Boot Start End Blocks Id System
/dev/sdb1 1 3916 31455238+ 83 Linux
...多了一块分区信息
格式化分区
一个命令就可以搞定了
# mkfs.ext4 /dev/sdb1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1966080 inodes, 7863809 blocks
393190 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
240 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 26 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.创建新卷标(可忽略）
这一步，我看到有些人做了，有些人没有做，于是查了下资料。
可以看下参考 e2label命令 后面没用上，可以不操作的。
# e2label /dev/sdb1 /data检查一下
# e2label /dev/sdb1
/data挂载
创建挂载目录，跟上一步一致
mkdir /data为了开机自动挂载，还需要编辑 /etc/fstab 文件，文件后面添加一行
/dev/sdb1 /data ext4 defaults 0 0有些可能对这个配置文件不太熟悉，请参见[fatab中文解释](https://wiki.archlinux.org/index.php/Fstab_(%E7%AE%80%E4%BD%93%E4%B8%AD%E6%96%87)
测试
# mount -a
# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_orangleliu-lv_root
6.5G 3.2G 3.0G 52% /
tmpfs 499M 0 499M 0% /dev/shm
/dev/sda1 477M 29M 424M 7% /boot
/dev/sdb1 30G 44M 28G 1% /data然后重启下，再次查看挂载情况，正常挂载，成功。