11.恢复逻辑卷到原来的大小（试着按扩展逻辑卷相反的步骤做，看是否能成功）：
首先卸载或者改为只读模式
[root@ ~]# umount /data-lv
先减小文件系统，再减小逻辑卷
减小文件系统之前 需要做强制检查
[root@ ~]# resize2fs /dev/testvg/testlv 40M
resize2fs 1.39 (29-May-2006)
Please run 'e2fsck -f /dev/testvg/testlv' first.
（这个命令应该是运行不成功的，因为文件系统要求，在重新调整文件系统之前，必须要强制检查一下，所以你要先用fsck做一次强制检查，然后再运行该命令）
强制检查
[root@ ~]# e2fsck -f /dev/testvg/testlv
[root@ ~]# e2fsck -f /dev/testvg/testlv
e2fsck 1.39 (29-May-2006)
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/testvg/testlv: 11/24576 files (9.1% non-contiguous), 8191/94208 blocks
[root@ ~]# resize2fs /dev/testvg/testlv 40M
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/testvg/testlv to 40960 (1k) blocks.
The filesystem on /dev/testvg/testlv is now 40960 blocks long.
[root@ ~]# lvresize -L 40M /dev/testvg/testlv
WARNING: Reducing active logical volume to 40.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce testlv? [y/n]: y
Reducing logical volume testlv to 40.00 MB
Logical volume testlv successfully resized
[root@ ~]# mount /dev/testvg/testlv /data
二、在LVM中更换硬盘
1.初始化分区
2.创建物理卷
[root@ ~]# pvcreate /dev/sda9
Physical volume "/dev/sda9" successfully created
3.把该物理卷加入到卷组testvg
[root@ ~]# vgextend testvg /dev/sda9
Volume group "testvg" successfully extended
查看卷组容量
[root@ ~]# vgdisplay
--- Volume group ---
VG Name testvg
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 7
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 3
Act PV 3
VG Size 5.60 GB
PE Size 4.00 MB
Total PE 1434
Alloc PE / Size 10 / 40.00 MB
Free PE / Size 1424 / 5.56 GB
VG UUID UJrKI9-NSrt-vhV8-iwoR-pN7i-MhQp-PxPcPr
4.查看物理卷详情，为数据转移做准备
[root@ ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda7
VG Name testvg
PV Size 1.87 GB / not usable 1.96 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 478
Free PE 468
Allocated PE 10
PV UUID pJxudP-iM6G-BNbv-Nx0a-cDqM-FAw1-51WeDz
--- Physical volume ---
PV Name /dev/sda8
VG Name testvg
PV Size 1.87 GB / not usable 1.96 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 478
Free PE 478
Allocated PE 0
PV UUID 7fOpr3-5cEC-1Gph-BmnY-Zj2I-UZo8-JwcUAW
--- Physical volume ---
PV Name /dev/sda9
VG Name testvg
PV Size 1.87 GB / not usable 1.96 MB
Allocatable yes
PE Size (KByte) 4096
Total PE 478
Free PE 478
Allocated PE 0
PV UUID xxNAtZ-a3RO-lN9D-UN1X-atq2-p5q9-HyEO8a
进/dev/sda7 有数据，需转移到/dev/sda9