LVM扩容、缩减和删除
常用命令：
lvextend：LV扩容
vgextend：VG扩容
lvreduce：LV缩减
vgreduce：VG缩减
lvremove：LV删除
vgremove：VG删除
pvmove：PV数据移动到所属逻辑卷的其它物理卷
pvremove：PV删除
vgchange：VG状态改变
一、LVM扩容
1、LV扩容之前，先查看LV和所属VG可用容量（VFree）
[root@localhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
LV1 VG1 -wi-ao---- 4.00g
[root@localhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 VG1 lvm2 a-- 2.00g 0
/dev/sdb2 VG1 lvm2 a-- 2.00g 8.00m
/dev/sdb3 lvm2 --- 2.01g 2.01g
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VG1 2 1 0 wz--n- 4.01g 8.00m
LV1大小为4G，VG1的VFree大小8M。要给LV增加2G容量，VG1可用剩余仅为8M，因为此需要给VG1扩容，将一个新的分区sdb3添加到卷组中：
[root@localhost ~]# vgextend VG1 /dev/sdb3
Volume group "VG1" successfully extended
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VG1 3 1 0 wz--n- 6.01g 2.01g
2、现在VG1的VFree为2.01G，可以直接给LV1扩容：
[root@localhost ~]# lvextend -L +2G /dev/mapper/VG1-LV1
Size of logical volume VG1/LV1 changed from 4.00 GiB (1024 extents) to 6.00 GiB (1536 extents).
Logical volume LV1 successfully resized
[root@localhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
LV1 VG1 -wi-ao---- 6.00g
注：也可以使用 lvextend -L 6G /dev/mapper/VG1-LV1直接扩容到6G
3、对文件系统进行扩容
LV1容量已扩容到6G，现在查下LV1的挂载点/LV1容量:
[root@localhost ~]# df -h /LV1
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VG1-LV1 3.9G 8.0M 3.7G 1% /LV1
/LV1容量为3.9G，而刚刚已将LV1扩容到6G，这是为什么呢？
因为刚才仅仅扩容了逻辑卷LV1的容量，而没有文件系统扩容，因此需要对文件系统扩容:
[root@localhost ~]# resize2fs /dev/mapper/VG1-LV1
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/VG1-LV1 is mounted on /LV1; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/mapper/VG1-LV1 to 1572864 (4k) blocks.
The filesystem on /dev/mapper/VG1-LV1 is now 1572864 blocks long.
[root@localhost ~]# df -h
/dev/mapper/VG1-LV1 5.8G 8.0M 5.5G 1% /LV1
到此/LV1已经扩容成功！
二、LV缩减，先卸载挂载点，再对文件系统进行缩减，最后缩减逻辑卷LV
1、先卸载挂载点：
[root@localhost ~]# umount /LV1/
[root@localhost ~]# mount -l
/dev/sda2 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1 on /boot type ext4 (rw)
/dev/sda3 on /usr type ext4 (rw)
/dev/sr0 on /mnt type iso9660 (ro) [CentOS_6.6_Final]
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
2、缩减文件系统:
[root@localhost ~]# resize2fs /dev/mapper/VG1-LV1 4G
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mapper/VG1-LV1 to 1048576 (4k) blocks.
The filesystem on /dev/mapper/VG1-LV1 is now 1048576 blocks long.
注：将文件系统/dev/mapper/VG1-LV1缩减到4G
3、缩减逻辑卷LV：
[root@localhost ~]# lvreduce -L -2G /dev/mapper/VG1-LV1
WARNING: Reducing active logical volume to 4.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce LV1? [y/n]: y
Size of logical volume VG1/LV1 changed from 6.00 GiB (1536 extents) to 4.00 GiB (1024 extents).
Logical volume LV1 successfully resized
4、挂载、查看lv和挂载点大小 ：
[root@localhost ~]# mount /dev/mapper/VG1-LV1 /LV1/
[root@localhost ~]# df -h
/dev/mapper/VG1-LV1 3.9G 8.0M 3.7G 1% /LV1
[root@localhost ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
LV1 VG1 -wi-ao---- 4.00g
三、LVM删除（LVM删除之前，请对重要数据备份到其它分区或LVM分区上）
删除LV，VG顺序：卸载挂载的逻辑卷,删除相应的逻辑卷，再删除卷组，最后删除物理卷PV。1、卸载挂载的逻辑卷
[root@localhost ~]# umount /LV1/
2、删除相应的逻辑卷LV
删除相应的逻辑卷前，需要先使用命令vgchange将活动的逻辑组停止：
[root@localhost ~]# vgchange -an VG1
0 logical volume(s) in volume group "VG1" now active
注：-a是available的缩写，y表示yes，n表示no
查看逻辑卷LV路径：
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Path /dev/VG1/LV1
删除逻辑卷LV:
[root@localhost ~]# lvremove /dev/VG1/LV1
Logical volume "LV1" successfully removed
3、删除逻辑卷组VG
[root@localhost ~]# vgremove VG1
Volume group "VG1" successfully removed
查看卷组VG1是否删除成功：
[root@localhost ~]# vgdisplay
No volume groups found
4、删除物理卷PV
查看PV信息
[root@localhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sdb1 lvm2 --- 2.01g 2.01g
/dev/sdb2 lvm2 --- 2.01g 2.01g
/dev/sdb3 lvm2 --- 2.01g 2.01g
删除PV：
[root@localhost ~]# pvremove /dev/sdb{1,2,3}
Labels on physical volume "/dev/sdb1" successfully wiped
Labels on physical volume "/dev/sdb2" successfully wiped
Labels on physical volume "/dev/sdb3" successfully wiped
验证PV删除成功与否：
[root@localhost ~]# pvs
如果只想将某个分区从物理卷中删除，首先使用使用pvmove将该物理馆上的数据移到别的物理卷，再使用vgreduce命令删除该物理卷。这样这个物理卷就像普通分区一样使用了。
[root@localhost ~]# pvmove /dev/sdb1
/dev/sdb1: Moved: 0.6%
/dev/sdb1: Moved: 39.6%
/dev/sdb1: Moved: 78.6%
/dev/sdb1: Moved: 100.0%
[root@localhost ~]# vgreduce VG1 /dev/sdb1
Removed "/dev/sdb1" from volume group "VG1"