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。
[[email protected] /]# 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:
[[email protected] /]# 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
[[email protected] /]# mount /dev/liuhg_disk/home /home
[[email protected] /]# 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。
