Linux 虚拟机扩容

由于在装软件，原来的20G空间不够使用，需要扩容操作。

1.关闭虚拟机

2.点击编辑虚拟机设置

选中硬盘，添加，硬盘，推荐，确定大小，完成。

2.启动虚拟机

查看磁盘使用情况：

[root@master ~]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2        18G  .0G   14G  % /
tmpfs           931M   80K  931M   % /dev/shm
/dev/sda1       291M   39M  238M  % /boot
/dev/sr0        .6G  .6G      % /media/RHEL_6. x86_64 Disc 

查看我们新的磁盘

对新加的硬盘进行分区，格式化，因为我的磁盘名称是/dev/sdb，所以输入 fdisk /dev/sdb命令：

[root@master ~]#  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 0xc2e1095b.
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)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1): 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652):
Using default value 652

Command (m for help): p

Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 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: 0xc2e1095b

Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         652     5237158+  83  Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

下一步，查看

格式化：

另一种格式化：mkfs -t ext3 /dev/sdb1

[root@master ~]# cd /
[root@master /]# ls
bin   dev  home  lib64       media  opt   root  selinux  sys  usr
boot  etc  lib   lost+found  mnt    proc  sbin  srv      tmp  var
[root@master /]# mkdir exapp
[root@master /]# mount /dev/sdb1 /exapp/
[root@master /]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2        18G  .0G   14G  % /
tmpfs           931M   72K  931M   % /dev/shm
/dev/sda1       291M   39M  238M  % /boot
/dev/sdb1       5.0G  139M  4.6G   3% /exapp

这个是挂载上了

开机自动挂载，则修改 /etc/fstab 文件，在这个文件里面添加一行： 
/dev/sdb1      /exapp       ext3    defaults        0      0

然而：我想扩大 / 下的空间 ，关闭虚拟机，重新给虚拟机分配2G的空间，启动

对磁盘进行分区

[root@master master]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x1b0e6bd8.
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)

Command (m for help): n     
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4):
First cylinder (1-261, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-261, default 261):
Using default value 261

Command (m for help): p

Disk /dev/sdc: 2147 MB, 2147483648 bytes
255 heads, 63 sectors/track, 261 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: 0x1b0e6bd8

Device Boot      Start         End      Blocks   Id  System
/dev/sdc4               1         261     2096451   83  Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

[root@master dev]# df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2        18G  3.0G   14G  18% /
tmpfs           931M   72K  931M   1% /dev/shm
/dev/sda1       291M   39M  238M  14% /boot
/dev/sdb1       5.0G  139M  4.6G   3% /exapp

[root@master master]# pvcreate /dev/sdc4            --  //创建物理卷
  dev_is_mpath: failed to get device for 8:36
  Physical volume "/dev/sdc4" successfully created

查看新建的物理卷和大小，使用pvdisplay命令。

为啥我的根目录下没有卷组？

根目录下有卷组的话，vgextend ubuntu14-vg /dev/sdc4

vgdisplay 会显示一个卷组信息

lvresize -L +120G /dev/mapper/ubuntu14--vg-root

resize2fs  /dev/mapper/ubuntu14--vg-root

df -h

应该会添加成功。