今天弄了台vps，30G的硬盘，但是df看了下只有10G，难道商家偷梁换柱了，然后用fdisk看了下，发现还有20G未分区的空间。遂写下这篇文章，将这些硬盘空间直接加入根分区。废话少说：

首先#fdisk -l查看硬盘信息

# lvm
lvm>vgdisplay 可以先看卷组是否还有剩余空间可以扩展，有的话直接扩展，没有或不够的话把新的硬盘添加进去
— Volume group —
VG Name VolGroup00
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 7.88 GB
PE Size 32.00 MB
Total PE 252
Alloc PE / Size 252 / 7.88 GB
Free PE / Size 0 / 0
VG UUID 0U8dPB-UTJZ-Mdv5-eZJM-Xj7f-gR1M-63BcCh
lvm>pvcreate /dev/sdb 使用新的整个硬盘创建一个lvm物理卷
lvm>vgextend /dev/VolGroup00 /dev/sdb 把新的物理卷添加到卷组中
lvm>vgdisplay 可以看到已分配空间和剩余未分配空间 All PE / Size 和 Free PE / Size
— Volume group —
VG Name VolGroup00
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 15.84 GB
PE Size 32.00 MB
Total PE 507
Alloc PE / Size 252 / 7.88 GB
Free PE / Size 255 / 7.97 GB
VG UUID 0U8dPB-UTJZ-Mdv5-eZJM-Xj7f-gR1M-63BcCh
lvm>lvextend -L +7.9G /dev/VolGroup00/LogVol00 扩展逻辑卷大小
lvm>vgdisplay
lvm>pvdisplay
lvm>lvdisplay 可以看到已经添加了
— Logical volume —
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID QtNkTM-TeSo-WnZD-fSUr-6k1F-5aLX-zAIfSQ
LV Write Access read/write
LV Status available
# open 1
LV Size 14.78 GB
Current LE 473
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0

— Logical volume —
LV Name /dev/VolGroup00/LogVol01
VG Name VolGroup00
LV UUID bhTEBX-t8XK-zGku-NCzx-eolz-Anvj-jUMUER
LV Write Access read/write
LV Status available
# open 1
LV Size 1.00 GB
Current LE 32
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
lvm>quit
# resize2fs -p /dev/VolGroup00/LogVol00 修改文件系统大小以实现扩充空间
# df -h

第二种情况：只添加一个新分区
# df -h 可以看到新添加的硬盘/dev/sdb1
# lvm
lvm>pvcreate /dev/sdb1 使用新的硬盘创建一个lvm物理卷
lvm>vgextend /dev/VolGroup00 /dev/sdb1
lvm>vgdisplay 可以看到已分配空间和剩余未分配空间 All PE / Size 和 Free PE / Size
lvm>lvextend -L +5G /dev/VolGroup00/LogVol00
lvm>vgdisplay
lvm>pvdisplay
lvm>lvdisplay
lvm>quit
# resize2fs -p /dev/VolGroup00/LogVol00 扩展
# df -h