扩展后执行fdisk -l查看是否成功
[root@localhost ~ ]# fdisk - l
Disk / dev / sda: 16.1 GB, 16106127360 bytes
255 heads, 63 sectors / track, 1958 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/ dev / sda1 * 1 6 48163 + 83 Linux
/ dev / sda2 7 515 4088542 + 83 Linux
/ dev / sda3 516 1239 5815530 83 Linux
/ dev / sda4 1240 1305 530145 5 Extended
/ dev / sda5 1240 1305 530113 + 82 Linux swap / Solaris
可见sda已经扩展成为16G，但是没分配给文件系统
继续执行fdisk /dev/sda进行新建磁盘
[root@localhost ~ ]# fdisk / dev / sda
The number of cylinders for this disk is set to 1958 .
There is nothing wrong with that, but this is larger than 1024 ,
and could in certain setups cause problems with:
1 ) software that runs at boot time (e.g., old versions of LILO)
2 ) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS / 2 FDISK)
Command (m for help): n
No free sectors available
前面执行fdisk -l的时候明明最后才是1305柱面，而且应该有1958柱面，为什么说没有空闲的扇区。
再看看fdisk -l执行结果，原来是/dev/sda5分配了作为swap分区，找到原因了就容易解决。
1.关闭swap分区# swapoff /dev/sda5
2.删除sda4和sda5.
[root@localhost ~ ]# fdisk / dev / sda
The number of cylinders for this disk is set to 1958 .
There is nothing wrong with that, but this is larger than 1024 ,
and could in certain setups cause problems with:
1 ) software that runs at boot time (e.g., old versions of LILO)
2 ) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS / 2 FDISK)
Command (m for help): d
Partition number ( 1 - 5 ): 5
Command (m for help): d
Partition number ( 1 - 5 ): 4
3.建立扩展分区4，建立分区sda5，写入
Command (m for help): n
Command action
e extended
p primary partition ( 1 - 4 )
e
Selected partition 4
First cylinder ( 1240 - 1958 , default 1240 ):
Using default value 1240
Last cylinder or + size or + sizeM or + sizeK ( 1240 - 1958 , default 1958 ):
Using default value 1958
Command (m for help): n
First cylinder ( 1240 - 1958 , default 1240 ):
Using default value 1240
Last cylinder or + size or + sizeM or + sizeK ( 1240 - 1958 , default 1958 ):
Using default value 1958
Command (m for help): w
The partition table has been altered !