1.首先查看硬盘信息
fdisk -l 如果有硬盘有剩余空间就可以对其进行分区
[root@bogon 桌面]# fdisk -l
Disk /dev/sda: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 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: 0x000471ad
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 3851 30720000 83 Linux
/dev/sda3 3851 4106 2048000 82 Linux swap / Solaris
/dev/sda4 4106 10444 50912256 5 Extended
/dev/sda5 4106 10444 50911232 83 Linux
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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
#从上面看出/dev/sda空间已经用完了，/dev/sdb没有使用。
下面我们对/dev/sdb 进行分区
[root@bogon 桌面]# 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 0xfaa2aa49.
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): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition's system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)
fdisk选中/dev/sdb 输入m所有基本选项都出现，输入n新建分区
Command (m for help): n
Command action
e extended
p primary partition (1-4)
有扩展分区和主分区，逻辑分区在扩展分区中建立。注意到括号中的1-4，最多只能建四个主分区（包括扩展分区）。先建一个主分区：
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p #建主分区
Partition number (1-4): 1 #分区号为1
First cylinder (1-2610, default 1): #直接回车默认从第一个柱面开始划分
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +2G #加空间大小，这里有很多种选择：+后面单位可以接M，G，K（记得要大写）表示划分你所加的空间，也可以是柱面数。不管怎样都不能超过该磁盘剩余的空间否则无效。
Command (m for help): p #分好后查看分区信息，刚所做的所有一目了然。
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0xfaa2aa49
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
同上所述建立扩展分区：
Command (m for help): n
Command action
e extended
p primary partition (1-4)
e #建立扩展分区
Partition number (1-4): 4
First cylinder (263-2610, default 263):
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-2610, default 2610): +4G
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0xfaa2aa49
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb4 263 785 4200997+ 5 Extended
扩展分区建好我们就可以在扩展分区建立逻辑分区了
Command (m for help): n
Command action
l logical (5 or over)
p primary partition (1-4)
l #建逻辑分区
First cylinder (263-785, default 263):
Using default value 263
Last cylinder, +cylinders or +size{K,M,G} (263-785, default 785): +2G
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0xfaa2aa49
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb4 263 785 4200997+ 5 Extended
/dev/sdb5 263 524 2104483+ 83 Linux
上面显示已经建好一个主分区，一个逻辑分区，但是这些现在还没有生效我们需要保存退出。
Command (m for help): w #保存退出
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@bogon 桌面]# fdisk -l
Disk /dev/sda: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 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: 0x000471ad
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 3851 30720000 83 Linux
/dev/sda3 3851 4106 2048000 82 Linux swap / Solaris
/dev/sda4 4106 10444 50912256 5 Extended
/dev/sda5 4106 10444 50911232 83 Linux
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0xfaa2aa49
Device Boot Start End Blocks Id System
/dev/sdb1 1 262 2104483+ 83 Linux
/dev/sdb4 263 785 4200997+ 5 Extended
/dev/sdb5 263 524 2104483+ 83 Linux
再次查看就看到了/dev/sdb的分区信息，虽然现在我们看到进行分区了，但是内核kenel还没有识别为了不要重启将分区表写入kenel我们要用到partprobe工具：使kenel重新读取分区表。
[root@bogon 桌面]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (设备或资源忙). As a result, it may not reflect all of your changes until after reboot.
kenel识别分区表后，我们还不能使用它要对其进行格式化。mkfs.加文件系统格式，扩展分区是不能格式化的。
[root@bogon 桌面]# mkfs.ext4 /dev/sdb1 #格式化成ext4文件格式（要分区格式化，不能将整个硬盘格式化）
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=541065216
17 block groups
32768 blocks per group, 32768 fragments per group
7744 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
正在写入inode表: 完成
Creating journal (16384 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 30 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@bogon 桌面]# mkfs.ext4 /dev/sdb5 #格式化逻辑分区
mke2fs 1.41.12 (17-May-2010)
文件系统标签=
操作系统:Linux
块大小=4096 (log=2)
分块大小=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
131648 inodes, 526120 blocks
26306 blocks (5.00%) reserved for the super user
第一个数据块=0
Maximum filesystem blocks=541065216
17 block groups
32768 blocks per group, 32768 fragments per group
7744 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912
正在写入inode表: 完成
Creating journal (16384 blocks): 完成
Writing superblocks and filesystem accounting information: 完成
This filesystem will be automatically checked every 39 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
格式化后就可以使用了
[root@bogon 桌面]# mkdir /bak
[root@bogon 桌面]# mount -o loop /dev/sdb1 /bak #挂载该分区到/bak
[root@bogon 桌面]# df -TH #查看当前硬盘挂载信息
文件系统 类型 容量 已用 可用 已用%% 挂载点
/dev/sda5 ext4 52G 3.9G 45G 8% /
tmpfs tmpfs 528M 279k 528M 1% /dev/shm
/dev/sda1 ext4 204M 28M 166M 15% /boot
/dev/sda2 ext4 31G 2.9G 27G 10% /usr
.host:/ vmhgfs 144G 41G 104G 29% /mnt/hgfs
/ios/RHEL6.3.iso
iso9660 3.2G 3.2G 0 100% /guazai
/dev/sdb1 ext4 2.2G 71M 2.0G 4% /bak
