一直都说LVM可以在线增加空间，一直都没有试过
下面小试一下：
1.增加硬盘
2.创建PV
3.添加PV到VG
4.扩展LV
1.增加硬盘
该干嘛干嘛
添加后需要重启（有知道不用重启的办法吗）
--这个是新添加的硬盘
[root@localhost ~]# fdisk -l /dev/sdb
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/sdb doesn't contain a valid partition table
2.创建PV
--命令很简单
--命令很简单
[root@localhost ~]# pvcreate /dev/sdb
Physical volume "/dev/sdb" successfully created
--可以看到新的PV了
[root@localhost ~]# pvdisplay
/dev/hdc: open failed: No medium found
--- Physical volume ---
PV Name /dev/sda2
VG Name VolGroup00
PV Size 9.90 GB / not usable 22.76 MB
Allocatable yes (but full)
PE Size (KByte) 32768
Total PE 316
Free PE 0
Allocated PE 316
PV UUID n5fS6M-jBiH-n9vU-pBTd-iOCv-BbTe-BUeNZo
"/dev/sdb" is a new physical volume of "5.00 GB"
--- NEW Physical volume ---
PV Name /dev/sdb
VG Name
PV Size 5.00 GB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID TDs3mN-3ON3-eHbl-cohr-7Hr3-8608-jiLlXG
3.添加PV到VG
--指定对应的VG和PV
[root@localhost ~]# vgextend VolGroup00 /dev/sdb
Volume group "VolGroup00" successfully extended
--看到新的5G添加到VG里面了，状态是没有分配
[root@localhost ~]# vgdisplay
--- 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 14.84 GB
PE Size 32.00 MB
Total PE 475
Alloc PE / Size 316 / 9.88 GB
Free PE / Size 159 / 4.97 GB
VG UUID x1uyPD-qBgE-2yQV-T1Cb-IGIz-e4LB-fghf1W
4.扩展LV
--先添加2G练手
[root@localhost ~]# lvextend -L +2G /dev/VolGroup00/LogVol00
Extending logical volume LogVol00 to 10.88 GB
Logical volume LogVol00 successfully resized
--成功后还未看到新的空间
[root@localhost ~]# df -m
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
8804 7362 988 89% /
--需要手动刷新
[root@localhost ~]# resize2fs /dev/VolGroup00/LogVol00
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 2850816 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 2850816 blocks long.
--现在就完成了
[root@localhost ~]# df -m
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
10788 7365 2867 72% /
若需要先缩小则使用以下命令：
lvreduce -L -20G /dev/mapper/vg_mysvr-lv_home
resize2fs /dev/mapper/vg_my-lv_home
lvextend -L +20G /dev/mapper/vg_mysvr-lv_root
resize2fs /dev/mapper/vg_mysvr-lv_root
