linux动态增加LV空间
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
[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% /