要想扩充虚拟机centos 空间，必须先扩充虚拟机本身物理空间.本文只描述如何增加centos系统的根目录空间。以下内容,需要输入命令以红色标出,关键输出内容以蓝色标出。

1 查看磁盘情况

首先登陆root用户,然后使用#fdisk -l

Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
/dev/sda2 64 2611 20458496 8e Linux LVM
 
Disk /dev/mapper/vg_zxw-lv_root: 18.8 GB, 18832424960 bytes
255 heads, 63 sectors/track, 2289 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
 
Disk /dev/mapper/vg_zxw-lv_root doesn't contain a valid partition table
 
Disk /dev/mapper/vg_zxw-lv_swap: 2113 MB, 2113929216 bytes
255 heads, 63 sectors/track, 257 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

2 创建新的主分区

执行命令 #fdisk /dev/sda之后会出现一系列信息

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 //“ 列出fdisk的帮助”
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)
 
Command (m for help):n //” 命令n用于添加新分区"
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4):3
First cylinder (2611-3916, default 2611): //此时，fdisk又会让你选择该分区的开始值这个就是分区的Start 值（start cylinder）；这里最好直接按回车，
Using default value 2611
Last cylinder, +cylinders or +size{K,M,G} (2611-3916, default 3916): //此时，fdisk又会让你选择该分区的开始值这个就是分区的End 值这里最好直接按回车
Using default value 3916
 
Command (m for help): w //w "保存所有并退出，分区划分完毕".q不保存退出
The partition table has been altered!
 
Calling ioctl() to re-read partition table.
 
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

3 修改分区为LVM

#fdisk /dev/sda
 
Command (m for help): m
Command (m for help): t //改变分区系统id
 
Partition number (1-4): 3 //指定分区号
Hex code (type L to list codes): 8e
Command (m for help): w

4 重启系统后登录（否则无法扩展分区）

5 格式化改新添加的分区

#fdisk -l 
 
 
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
/dev/sda2 64 2611 20458496 8e Linux LVM
/dev/sda3 2611 3916 10483750 8e Linux LVM
 
#mkfs -t ext3 /dev/sda3

6 扩展新分区

#lvs
#pvcreate  /dev/sda3
#vgextend  vg_ylitech  /dev/sda3
#vgdisplay
--- Volume group ---
VG Name vg_ylitech
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 19.51 GiB
PE Size 4.00 MiB
Total PE 4994
Alloc PE / Size 4994 / 19.51 GiB
Free PE / Size 4994 / 10.01GB
VG UUID sqBgTs-iA8x-tCXZ-KYxK-SyWS-TfXQ-uBsLaR
(主要查看Free PE / Size 4994 / 10.01GB，说明我们最多可以有10.01GB的扩充空间。我一般选择小于10.01GB)
然后执行以下命令（注意空格）
# lvextend -L+5G /dev/vg_ylitech/lv_root /dev/sda3
// 添加硬盘
# sudo resize2fs /dev/mapper/vg_ylitech-lv_root
//在主分区自动扩展添加的新磁盘

 

完成之后,可以使用df -h 命令,查看磁盘情况,这是已经扩展完成了。