云主机中LINUX（CentOS 5.6）系统默认只有10G空间，如何将其它可用空间加入至"/"根分区下直接使用，不必重新启动系统，也不必重新挂在分区！
前提要求“/”根分区使用LVM。这个感谢旺角的先见之明！话不多说，开始操作：
一、将空闲的10G磁盘（/dev/hdb）做成LVM分区，由于一开始没有想到要做教程，所以没有保存分区的方式，大致说一下
1使用fdisk /dev/hdb命令分区
[root@localhost ~]# fdisk /dev/hdb
The number of cylinders for this disk is set to 20805.
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
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
然后设置分区块的大小，默认就好。两次回车，即完成
然后设置分区的类型，
输入t 设置分区类型
输入3 3号分区
输入8e 设置为LVM
[root@localhost ~]# fdisk -l --查看分区
Disk /dev/hda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/hda1 * 1 13 104391 83 Linux
/dev/hda2 14 1305 10377990 8e Linux LVM
Disk /dev/hdb: 10.7 GB, 10737418240 bytes
16 heads, 63 sectors/track, 20805 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Device Boot Start End Blocks Id System
/dev/hdb3 1 20805 10485688+ 8e Linux LVM 已经将可用10G空间分成LVM类型了
[root@localhost ~]# df -h 查看容量 现在根分区是7.7G
文件系统 容量 已用 可用 已用% 挂载点
/dev/mapper/VolGroup00-LogVol00
7.7G 3.4G 4.0G 46% /
/dev/hda1 99M 22M 73M 23% /boot
tmpfs 506M 0 506M 0% /dev/shm
[root@localhost ~]# pvcreate /dev/hdb3 创建物理卷
Physical volume "/dev/hdb3" successfully created
[root@localhost ~]# vgextend /dev/VolGroup00 /dev/hdb3 将物理卷加入逻辑卷中
/dev/hdc: open failed: 找不到介质
Volume group "VolGroup00" successfully extended
[root@localhost ~]# vgdisplay 查看卷空间
--- 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 19.84 GB //已经20G了，完成第一步工作了。
PE Size 32.00 MB
Total PE 635
Alloc PE / Size 316 / 9.88 GB
Free PE / Size 319 / 9.97 GB
VG UUID saeQq7-ZDfs-tfMK-WXwc-1Dp4-zp0n-WPOffm
[root@localhost ~]# lvextend -L +10G /dev/VolGroup00/LogVol00 开始扩容了，在原来的LogVol00增加10G
Extending logical volume LogVol00 to 17.88 GB
Insufficient free space: 320 extents needed, but only 319 available //这里执行错误了，原因是实际没有10G，只有9G多一点。
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID KvXRSp-5opU-NpMr-xfat-x9rI-m88t-nSjGTV
LV Write Access read/write
LV Status available
# open 1
LV Size 7.88 GB
Current LE 252
Segments 1
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 ee8srq-8YwD-DDUk-rQEs-0IoY-B6U5-YWr2oz
LV Write Access read/write
LV Status available
# open 1
LV Size 2.00 GB
Current LE 64
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@localhost ~]# lvextend -L +10737M /dev/VolGroup00/LogVol00
Rounding up size to full physical extent 10.50 GB
Extending logical volume LogVol00 to 18.38 GB
Insufficient free space: 336 extents needed, but only 319 available
[root@localhost ~]# lvextend -L +10537M /dev/VolGroup00/LogVol00
Rounding up size to full physical extent 10.31 GB
Extending logical volume LogVol00 to 18.19 GB
Insufficient free space: 330 extents needed, but only 319 available
[root@localhost ~]# lvextend -L +10037M /dev/VolGroup00/LogVol00 扩容10037M才成功。汗！！！！！！！！！！！！
Rounding up size to full physical extent 9.81 GB
Extending logical volume LogVol00 to 17.69 GB
Logical volume LogVol00 successfully resized
[root@localhost ~]# lvdisplay 查看一下大小，看不是已经扩展出来了
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID KvXRSp-5opU-NpMr-xfat-x9rI-m88t-nSjGTV
LV Write Access read/write
LV Status available
# open 1
LV Size 17.69 GB
Current LE 566
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 ee8srq-8YwD-DDUk-rQEs-0IoY-B6U5-YWr2oz
LV Write Access read/write
LV Status available
# open 1
LV Size 2.00 GB
Current LE 64
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@localhost ~]# resize2fs /dev/VolGroup00/LogVol00 //使增加的容量生效。
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 4636672 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 4636672 blocks long.
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID KvXRSp-5opU-NpMr-xfat-x9rI-m88t-nSjGTV
LV Write Access read/write
LV Status available
# open 1
LV Size 17.69 GB
Current LE 566
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 ee8srq-8YwD-DDUk-rQEs-0IoY-B6U5-YWr2oz
LV Write Access read/write
LV Status available
# open 1
LV Size 2.00 GB
Current LE 64
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@localhost ~]# df -h 再查看分区。已经有18G了。是不是很爽。
文件系统 容量 已用 可用 已用% 挂载点
/dev/mapper/VolGroup00-LogVol00
18G 3.4G 13G 21% /
/dev/hda1 99M 22M 73M 23% /boot
tmpfs 506M 0 506M 0% /dev/shm
[root@localhost ~]#
