最近在VMware虚拟机上使用Centos，用着用着，发现虚拟机的磁盘空间不够了。通过以下步骤成功扩展了根目录的磁盘空间
1、Centos 关机，选择编辑虚拟机设置，硬盘，在实用工具那里选择“扩展”
填写扩展的磁盘容量
点击扩展后，VMware会提示磁盘已成功扩展。您必须从客户机操作系统内部对磁盘重新进行分区和扩展文件系统。也就是说，这里扩展的磁盘空间，在操作系统里面还不可用，还没生效，需要在操作系统里面进行设置后才能使用。
2、启动客户机操作系统Centos，查看磁盘情况
输入指令
fdisk -l显示结果如下
Disk /dev/loop0: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 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/loop1: 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: 0x00000000
Disk /dev/sda: 37.6 GB, 37580963840 bytes
255 heads, 63 sectors/track, 4568 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: 0x000c8278
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 1306 9972736 8e Linux LVM
Disk /dev/mapper/vg_test001-lv_root: 9135 MB, 9135194112 bytes
255 heads, 63 sectors/track, 1110 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_test001-lv_swap: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 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/docker-253:0-264224-pool: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 65536 bytes
Disk identifier: 0x00000000其中，可以看到现在的分区情况如下
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 1306 9972736 8e Linux LVM3、创建分区 sda3
输入指令
fdisk /dev/sda然后根据命令提示创建分区，具体见以下 # 后面的注释
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): n # 输入 n 表示创建新分区
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3 # 输入 3 表示sda3，因为前面已经有两个了
First cylinder (1306-4568, default 1306): # 回车，按默认值
Using default value 1306
Last cylinder, +cylinders or +size{K,M,G} (1306-4568, default 4568): # 回车，按默认值
Using default value 4568
Command (m for help): w # 输入 w 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.再次查看分区情况
fdisk -l这时可以看到
Disk /dev/loop0: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 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/loop1: 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: 0x00000000
Disk /dev/sda: 37.6 GB, 37580963840 bytes
255 heads, 63 sectors/track, 4568 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: 0x000c8278
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 1306 9972736 8e Linux LVM
/dev/sda3 1306 4568 26206700 83 Linux
Disk /dev/mapper/vg_test001-lv_root: 9135 MB, 9135194112 bytes
255 heads, 63 sectors/track, 1110 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_test001-lv_swap: 1073 MB, 1073741824 bytes
255 heads, 63 sectors/track, 130 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/docker-253:0-264224-pool: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 65536 bytes
Disk identifier: 0x00000000其中，分区已变为3个了，但这时还没挂载，还不能用
Device Boot Start End Blocks Id System
/dev/sda1 * 1 64 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 64 1306 9972736 8e Linux LVM
/dev/sda3 1306 4568 26206700 83 Linux4、重启操作系统
reboot5、格式化新分区为ext3
输入指令
mkfs -t ext3 /dev/sda3结果为
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1638400 inodes, 6551675 blocks
327583 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
200 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 33 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.6、将物理硬盘分区初始化为物理卷，以便被LVM使用，输入指令
lvs
pvcreate /dev/sda37、向卷组中添加物理卷来增加卷组的容量
查看lvm组名，输入指令 df -h
[root@test001 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_test001-lv_root
8.3G 5.4G 2.5G 69% /
tmpfs 1001M 0 1001M 0% /dev/shm
/dev/sda1 477M 54M 394M 12% /boot其中，vg_test001 就是 根 所在的组名
输入指令，增加卷组的容量
vgextend vg_test001 /dev/sda38、查看可扩展的空间大小
输入指令，显示LNM卷组的元数据信息
vgdisplay结果为
--- Volume group ---
VG Name vg_test001
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 34.50 GiB
PE Size 4.00 MiB
Total PE 8831
Alloc PE / Size 2434 / 9.51 GiB
Free PE / Size 6397 / 24.99 GiB
VG UUID JuPKc8-Ydps-1bsN-0Wld-fbYS-0Hd2-NgvX1q其中 Free PE / Size 就是可供分配的*空间，最多有 24.99G，在扩展时输入小于该值
9、扩充磁盘空间
lvextend -L+24G /dev/mapper/vg_test001-lv_root /dev/sda310、使用e2fsck指令检查文件系统错误
e2fsck -a /dev/mapper/vg_test001-lv_root11、使用resize2fs指令来增大或者收缩未加载的“ext2/ext3”文件系统的大小
resize2fs /dev/mapper/vg_test001-lv_root12、查看扩展空间后的结果
[root@test001 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_test001-lv_root
32G 5.4G 26G 18% /
tmpfs 1001M 0 1001M 0% /dev/shm
/dev/sda1 477M 54M 394M 12% /boot可以看出，在根目录下磁盘空间已经扩容了，大功告成！