本来有台上面配置好CACTI的监控服务的虚拟机，一直是用来监控现在的服务器，这天连接上去，才发现这台机器当时是自己在本机上玩的，没想到会用在真实工作环境下，现在空间快不够了，需要给这台虚拟机扩下容量了，可是在线扩容我还真没高过，没办法，在弄台虚拟机来玩玩。。。

[root@localhost ~]# df

Filesystem           1K-blocks      Used Available Use% Mounted on

/dev/mapper/VolGroup00-LogVol00

6983168   2253172   4369548  35% /

/dev/sda1               101086     12056     83811  13% /boot

tmpfs                   257668         0    257668   0% /dev/shm

[root@localhost ~]# fdisk -l

Disk /dev/sda: 8589 MB, 8589934592 bytes

255 heads, 63 sectors/track, 1044 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

/dev/sda2              14        1044     8281507+  8e  Linux LVM

Disk /dev/sdb: 1073 MB, 1073741824 bytes

255 heads, 63 sectors/track, 130 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn't contain a valid partition table

上面是本机现在的清况，下面开始创建物理卷

[root@localhost ~]# pvcreate /dev/sdb

Physical volume "/dev/sdb" successfully created

[root@localhost ~]# pvdisplay                    ##可以用“pvdisplay”命令查看物理卷情况

--- Physical volume ---

PV Name               /dev/sda2

VG Name               VolGroup00

PV Size               7.90 GB / not usable 23.41 MB

Allocatable           yes (but full)

PE Size (KByte)       32768

Total PE              252

Free PE               0

Allocated PE          252

PV UUID               Up0jiK-5I0E-d5J5-wZSu-WIhX-aKRA-OR9Pjm

"/dev/sdb" is a new physical volume of "1.00 GB"               ###新建的物理卷

--- NEW Physical volume ---

PV Name               /dev/sdb

VG Name

PV Size               1.00 GB

Allocatable           NO

PE Size (KByte)       0

Total PE              0

Free PE               0

Allocated PE          0

PV UUID               zkullQ-PgoI-fHH4-xL3K-VLGm-JgMr-T7R1oA

下面就是将新添的物理卷加入到已有的逻辑卷组中

[root@localhost ~]# vgextend /dev/VolGroup00 /dev/sdb  /dev/cdrom: open failed: Read-only file system

/dev/cdrom: open failed: Read-only file system

Attempt to close device '/dev/cdrom' which is not open.

Volume group "VolGroup00" successfully extended

[root@localhost ~]# vgdisplay                ##查看卷组的空间

--- 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               8.84 GB

PE Size               32.00 MB

Total PE              283

Alloc PE / Size       252 / 7.88 GB                      ###原有的  Free  PE / Size       31 / 992.00 MB                    ##新加的扩容进去的空间

VG UUID               0q4Uy2-coR3-bLwU-izpJ-kLOC-PxO3-9Efm8H

###############################################################

[root@localhost ~]# lvdisplay                                               查看下分区

--- Logical volume ---

LV Name              /dev/VolGroup00/LogVol00

VG Name                VolGroup00

LV UUID                DDmERv-LIlu-cwXR-oM9t-33wj-l2ko-zw715W

LV Write Access        read/write

LV Status              available

# open                 1

LV Size                6.88 GB

Current LE             220

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                e0uO3o-HHrl-LFD1-iy3j-GSQc-U5mM-Q0GU4F

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

下面就开始扩容的操作了。。。

[root@localhost ~]#lvextend -L +1G /dev/VolGroup00/LogVol00  Extending logical volume LogVol00 to 7.88 GB

Insufficient free space: 32 extents needed, but only 31 available

###这里显示失败，空间不够，我的命令是加一个G的空间，但是空间不足。。。

[root@localhost ~]# lvextend -L +900M /dev/VolGroup00/LogVol00  Rounding up size to full physical extent 928.00 MB

Extending logical volume LogVol00 to 7.78 GB

Logical volume LogVol00 successfully resized

##成功了，我改为添加900M，其实在上面vgdisplay 的时候可以看到他添加了多少空间，但是当时我操作的时候，没注意看，呵呵。。。这个时候你在用lvdisplay命令看LV的空间的话，可以看到/dev/VolGroup00/LogVol00的空间已经增大了。。。

下面开始检查LVM设备对应inode和block之间的关系

[root@localhost ~]# e2fsck -f /dev/VolGroup00/LogVol00

e2fsck 1.39 (29-May-2006)

/dev/VolGroup00/LogVol00 is mounted.

WARNING!!!  Running e2fsck on a mounted filesystem may cause

SEVERE filesystem damage.

Do you really want to continue (y/n)? yes

/dev/VolGroup00/LogVol00: recovering journal

Pass 1: Checking inodes, blocks, and sizes

Pass 2: Checking directory structure

Pass 3: Checking directory connectivity

Pass 4: Checking reference counts

Pass 5: Checking group summary information

/dev/VolGroup00/LogVol00: ***** FILE SYSTEM WAS MODIFIED *****

/dev/VolGroup00/LogVol00: ***** REBOOT LINUX *****

/dev/VolGroup00/LogVol00: 108951/2064384 files (0.3% non-contiguous), 627952/2048000 blocks

最后是增加的容量生效

[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 2048000 (4k) blocks.

The filesystem on /dev/VolGroup00/LogVol00 is now 2048000 blocks long.

最后用df在看下现在的空间情况：

[root@localhost ~]# df

Filesystem           1K-blocks      Used Available Use% Mounted on

/dev/mapper/VolGroup00-LogVol00

7933376   2253184   5270604  30% /                            #本来是35%

/dev/sda1               101086     12056     83811  13% /boot

tmpfs                   257668         0    257668   0% /dev/shm

至此在虚拟机上，最简单的一个LVM扩容操作完毕，为日后查看写本文做备忘。