情况介绍：

一、由于硬盘或者分区的操作方式其实都一样，所以我这里就以分区为例。

二、/home分区2.6G，由如下pv组成：

/dev/sda5 100M

/dev/sda6 200M

/dev/sda7 300M

/dev/sda8 400M

/dev/sda9 500M

/dev/sda10 600M

/dev/sda11 500M

很碎对吧？^_^因为测试。

三、随机写了一堆文件进去，用量达到了2G，空闲500M

四、准备将sda6这个200M的PV卸掉（卸掉的容量必须小于空闲容量）

好了开始具体操作了。

卸载分区（缩小操作必须卸载才能进行）：

umount /home

缩小分区：

e2fsck -f /dev/liuhg_disk/home

resize2fs /dev/liuhg_disk/home 2200M

首先将分区缩小到2200M这是为了给sda6腾出空间，sda6为200M，而我腾出了400M，因此应该是足够的。

缩小逻辑卷：

lvreduce -L 2200M /dev/liuhg_disk/home

分区缩小了用到的逻辑卷也要随着缩小，并查看PV使用的状态：

pvdisplay -m

显示如下：

--- Physical volume ---
PV Name /dev/sda5
VG Name liuhg_disk
PV Size 103.26 MiB / not usable 3.26 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 25
Free PE 0
Allocated PE 25
PV UUID 5lnx52-b4jc-OOfZ-f2QA-ttdQ-DZeD-Ce3rb3

--- Physical Segments ---
Physical extent 0 to 24:
Logical volume /dev/liuhg_disk/home
Logical extents 0 to 24

--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 50
Free PE 0 <-----太悲剧了，sda6里写满了数据一点不剩
Allocated PE 50 <-----这50PE的数据要挪走才行，否则数据就丢了，并且存放的地方也必须是连续的至少50PE
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK

--- Physical Segments ---
Physical extent 0 to 49:
Logical volume /dev/liuhg_disk/home
Logical extents 25 to 74

--- Physical volume ---
PV Name /dev/sda7
VG Name liuhg_disk
PV Size 305.89 MiB / not usable 1.89 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 76
Free PE 76 <---这个分区有76个空余，因此预计装那50个是不会有问题的
Allocated PE 0
PV UUID 9CFnlx-CAEw-CSul-Rig9-FiCN-zK0a-oGmTEP

--- Physical Segments ---
Physical extent 0 to 75:
FREE

--- Physical volume ---
PV Name /dev/sda8
VG Name liuhg_disk
PV Size 407.87 MiB / not usable 3.87 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 101
Free PE 60
Allocated PE 41
PV UUID X0I8p0-x2xr-2xLG-QQD4-jbtS-3C4i-xPn4Bl

--- Physical Segments ---
Physical extent 0 to 40:
Logical volume /dev/liuhg_disk/home
Logical extents 471 to 511
Physical extent 41 to 100:
FREE

--- Physical volume ---
PV Name /dev/sda9
VG Name liuhg_disk
PV Size 509.84 MiB / not usable 1.84 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 127
Free PE 0
Allocated PE 127
PV UUID avJQaA-oMKt-NEoJ-ojBK-2Csc-1dca-1mh6Ue

--- Physical Segments ---
Physical extent 0 to 126:
Logical volume /dev/liuhg_disk/home
Logical extents 225 to 351

--- Physical volume ---
PV Name /dev/sda10
VG Name liuhg_disk
PV Size 603.98 MiB / not usable 3.98 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 150
Free PE 0
Allocated PE 150
PV UUID JlMIAF-A49n-M6HA-ZLXf-d8nS-pfZr-YeQsKT

--- Physical Segments ---
Physical extent 0 to 149:
Logical volume /dev/liuhg_disk/home
Logical extents 75 to 224

--- Physical volume ---
PV Name /dev/sda11
VG Name liuhg_disk
PV Size 478.47 MiB / not usable 2.47 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 119
Free PE 0
Allocated PE 119
PV UUID xnHJNA-tDVx-dryX-KM1x-g96Y-sptI-9iUOcU

--- Physical Segments ---
Physical extent 0 to 118:
Logical volume /dev/liuhg_disk/home
Logical extents 352 to 470

将sda6设置为离线状态：

pvchange -xn /dev/sda6

使用pvdisplay -m

显示如下：

……

--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO <-----表示已经关闭了该PV
PE Size 4.00 MiB
Total PE 50
Free PE 0
Allocated PE 50
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK

……
将sda6的数据移走：

pvmove -i 1 /dev/sda6

-i 1是每1秒钟报告一次数据迁移的进度。

[root@liuhg /]# pvmove -i 1 /dev/sda6
/dev/sda6: Moved: 38.0%
/dev/sda6: Moved: 84.0%
/dev/sda6: Moved: 100.0%

重新用pvdisplay -m

显示如下：

……

--- Physical volume ---
PV Name /dev/sda6
VG Name liuhg_disk
PV Size 203.92 MiB / not usable 3.92 MiB
Allocatable NO
PE Size 4.00 MiB
Total PE 50
Free PE 50 <----显示完全空闲和Total PE数一致
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK

……

从卷组里把sda6删除:

[root@liuhg /]# vgreduce liuhg_disk /dev/sda6
Removed "/dev/sda6" from volume group "liuhg_disk"

pvdisplay -m再看看吧：

--- NEW Physical volume --- <-----还告诉你这是一个新的PV ^_^
PV Name /dev/sda6
VG Name <-----空了
PV Size 203.92 MiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID S2ane6-nlFG-uSNR-35NP-Yxa6-cXRb-r8E8mK

到此vgdisplay -v能看到已经没有了/dev/sda6了。重新挂载/home

[root@liuhg /]# mount /dev/liuhg_disk/home /home
[root@liuhg /]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 2.0G 546M 1.3G 30% /
tmpfs 504M 0 504M 0% /dev/shm
/dev/mapper/liuhg_disk-home
2.2G 1.8G 42M 98% /home

进去看看数据，一个都没丢。