前言
最近搞Linux时，当初没有考虑完善，只分配了10GB的空间，启动mongodb时直接给我报了一个错误：可用空间太少，虽说加一个参数—smallfiles就可以解决问题，但这治标不治本。所以我参考Adding a New Disk Drive to an RHEL 6 System，记录下来，以供以后参考。
环境
Oracle VM VirtualBox搭建的虚拟机，主机cpu intel i5-4590,8G内存，系统win7 64位，Linux虚拟机的环境是centos6.5
在Linux中找到新硬盘
前提是你已经为虚拟机添加了一个新的硬盘。
切换root用户
[spider140@spider140 ~]$ ls /dev/sd*
/dev/sda /dev/sda1 /dev/sda2 /dev/sdb
在这里/dev/sda表示的硬盘被分成两个分区，由/dev/sda1, /dev/sda2表示。咱们新加的硬盘已经指派给/dev/sdb，现在没有为这个硬盘分配任何分区。
添加一个linux分区
[root@spider140 spider140]# 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 0x3590b300.
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):
通过键入c和u来关闭DOS适配模式和改变单元为扇区
Command (m for help): c
DOS Compatibility flag is not set
Command (m for help): u
Changing display/entry units to sectors
键入p查看当前分区数:
Command (m for help): p
Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x3590b300
Device Boot Start End Blocks Id System
如上所示，该硬盘没有任何分区。
现在开始添加分区
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4):
添加主分区
因为在这里我这想创建一个分区，所以启示扇区是1，截止扇区就是最后一个，指教键入两个回车使用默认值
First sector (2048-16777215, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-16777215, default 16777215):
Using default value 16777215
键入p查看当前分区
Disk /dev/sdb: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders, total 16777216 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x3590b300
Device Boot Start End Blocks Id System
/dev/sdb1 2048 16777215 8387584 83 Linux
键入w保存分区信息并退出
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
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