1.lvm管理設備，使設備的大小根據需要變化
pv:物理卷
pe:物理拓展分區
vg:物理卷組
lvm:邏輯卷
2.lvm的建立
（1）
劃分物理分區，並修改分區標籤爲1vm（lvm類型id爲8e）
pvcreate /dev/vdb1 ## 創建物理卷
vgcreate vg0 /dev/vdb1 ##創建物理卷組
lvcreate -L 100M -n lv0 vg0 ##創建邏輯卷
mkfs.xfs /dev/vg0/lv0 ##格式化設備
mount /dev/vg0/lv0 /westos ##設備掛載投入使用
[root@localhost ~]# pvcreate /dev/vdb1
Physical volume "/dev/vdb1" successfully created
[root@localhost ~]# mkdir /westos
[root@localhost ~]# chmod 777 /westos
[root@localhost ~]# ls -ld /westos
drwxrwxrwx. 2 root root 6 Nov 4 21:47 /westos
[root@localhost ~]#
[root@localhost ~]# vgcreate vg0 /dev/vdb1
Volume group "vg0" successfully created
[root@localhost ~]# lvcreate -L 100M -n lv0 vg0
Logical volume "lv0" created
[root@localhost ~]# mkfs.xfs /dev/vg0/lv0
meta-data=/dev/vg0/lv0 isize=256 agcount=4, agsize=6400 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0
data = bsize=4096 blocks=25600, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal log bsize=4096 blocks=853, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@localhost ~]# mount /dev/vg0/lv0 /westos
監控：watch -n 1 ‘pvs;echo +++++++;vgs;echo ++++++;lvs;echo ======;df -h /westos’
Every 1.0s: pvs;echo +++++++;vgs;echo ++++++;lvs;echo ======;df -h ... Sat Nov 4 22:10:56 2017
PV VG Fmt Attr PSize PFree
/dev/vdb1 vg0 lvm2 a-- 496.00m 0
/dev/vdb2 vg0 lvm2 a-- 496.00m 292.00m
+++++++
VG #PV #LV #SN Attr VSize VFree
vg0 2 1 0 wz--n- 992.00m 292.00m
++++++
LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert
##### lv0 vg0 -wi-ao---- 700.00m
======
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg0-lv0 697M 6.0M 691M 1% /westos
(2)
pvcreate /dev/vdb1
vgcreate -s 4M westos /dev/vdb1 ##生成一個物理拓展分區大小爲4M，物理卷組westos爲4M
lvcreate -l 50 -n lv0 westos ##邏輯卷組爲200M
3.lvm的拉深
當vg中剩餘容量充足的時候
lvextend -L 400M /dev/vg0/lv0 ##將設備從100M拉深爲400M
xfs_growfs /dev/vg0/lv0 ##將文件系統拉深[root@localhost ~]# lvextend -L 400M /dev/vg0/lv0
Extending logical volume lv0 to 400.00 MiB
Logical volume lv0 successfully resized
[root@localhost ~]# xfs_growfs /dev/vg0/lv0
meta-data=/dev/mapper/vg0-lv0 isize=256 agcount=4, agsize=6400 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0
data = bsize=4096 blocks=25600, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=853, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 25600 to 102400
當vg中剩餘容量不足的時候
新建分區/dev/vdb2，改標籤爲lvm
pvcreate /dev/vdb2 ##將/dev/vdb2添加到pv中
vgextend vg0 /dev/vdb2 ##將/dev/vdb2添加到vg0中
lvextend -L 700M /dev/vg0/lv0 ##將/dev/vg0/lv0設備拉深到700M
xfs_growfs /dev/vg0/lv0 ##拉深文件系統
[root@localhost ~]# pvcreate /dev/vdb2
Physical volume "/dev/vdb2" successfully created
[root@localhost ~]# vgectend vg0 /dev/vdb2
bash: vgectend: command not found...
[root@localhost ~]# vgextend vg0 /dev/vdb2
Volume group "vg0" successfully extended
[root@localhost ~]# lvextend -L 700M /dev/vg0/lv0
Extending logical volume lv0 to 700.00 MiB
Logical volume lv0 successfully resized
[root@localhost ~]# xfs_growfs /dev/vg0/lv0
meta-data=/dev/mapper/vg0-lv0 isize=256 agcount=16, agsize=6400 blks
= sectsz=512 attr=2, projid32bit=1
= crc=0
data = bsize=4096 blocks=102400, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=0
log =internal bsize=4096 blocks=853, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 102400 to 179200
[root@localhost ~]#
注意：擴容的極限爲18EB-1TB
4.在ext4文件系統中：
umount /dev/vg0/lv0 ##卸載設備
mkfs.ext4 /dev/vg0/lv0 ##格式化設備爲ext4
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
44832 inodes, 179200 blocks
8960 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=184549376
6 block groups
32768 blocks per group, 32768 fragments per group
7472 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
拉深
lvextend -L 400M /dev/vg0/lv0 ##將設備拉深到700M
resize2fs /dev/vg0/lv0 ##拉深文件系統縮減
umount /dev/vg0/lv0 ##卸載設備
e2fsck -f /dev/vg0/lv0 ##掃描設備上的數據,查看文件的大小,根據文件的大小縮減設備。
e2fsck 1.42.9 (28-Dec-2013)
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/vg0/lv0: 11/44832 files (0.0% non-contiguous), 7272/179200 blocks
resize2fs /dev/vg0/lv0 200M ##縮減文件系統
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/vg0/lv0 to 51200 (4k) blocks.
The filesystem on /dev/vg0/lv0 is now 51200 blocks long.
mount /dev/vg0/lv0 /westos/ ##掛載設備
lvreduce -L 200M /dev/vg0/lv0 ##縮減設備
WARNING: Reducing active and open logical volume to 200.00 MiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce lv0? [y/n]: y
Reducing logical volume lv0 to 200.00 MiB
Logical volume lv0 successfully resized
[root@localhost ~]# lvextend -L 400M /dev/vg0/lv0
Extending logical volume lv0 to 400.00 MiB
Logical volume lv0 successfully resized
5.對卷組
pvmove /dev/vdb1 /dev/vdb2 ##當要移除的分區存在數據時，需要把數據遷移到其他的pv中
vgreduce vg0 /dev/vdb1 ##移除卷組中的/dev/vdb1
pvremove /dev/vdb1 ##將/dev/vdb1從物理卷中移除[root@localhost ~]# pvmove /dev/vdb1 /dev/vdb2
/dev/vdb1: Moved: 100.0%
[root@localhost ~]# vgreduce vg0 /dev/vdb1
Removed "/dev/vdb1" from volume group "vg0"
[root@localhost ~]# pvremove /dev/vdb1
Labels on physical volume "/dev/vdb1" successfully wiped
[root@localhost ~]#
6.lvm快照
lvm快照： ##讀取數據讀取的是設備
lvcreate -L 100M -n lv0backup -s /dev/vg0/lv0
##對/dev/vg0/lv0進行快照，快照的大小爲100M，生成的快照文件爲v0backup。
mount /dev/vg0/lv0backup /westos/ ##掛載生成的快照
[root@localhost ~]# lvcreate -L 80M -n lv0backup -s /dev/vg0/lv0
Logical volume "lv0backup" created
[root@localhost ~]# mount /dev/vg0/lv0backup /westos/
[root@localhost ~]#
7.lvm的刪除
umount /dev/vg0/lv0backup ##卸載快照
lvremove /dev/vg0/lv0backup ##移除快照
lvremove /dev/vg0/lv0 ##移除邏輯卷
vgremove vg0 ##移除物理卷組
pvremove /dev/vdb2 ##將/dev/dvb2從物理卷中移除
fdisk /dev/vdb
[root@localhost ~]# umount /dev/vg0/lv0backup
umount: /dev/vg0/lv0backup: not mounted
[root@localhost ~]# lvremove /dev/vg0/lv0backup
Do you really want to remove active logical volume lv0backup? [y/n]: y
Logical volume "lv0backup" successfully removed
[root@localhost ~]# lvremove /dev/vg0/lv0
Do you really want to remove active logical volume lv0? [y/n]: y
Logical volume "lv0" successfully removed
[root@localhost ~]# vgremove vg0
Volume group "vg0" successfully removed
[root@localhost ~]# pvremove /dev/vdb2
Labels on physical volume "/dev/vdb2" successfully wiped
[root@localhost ~]# fdisk /dev/vdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): d
Partition number (1-3, default 3): 1
Partition 1 is deleted
Command (m for help): d
Partition number (2,3, default 3):
Partition 3 is deleted
Command (m for help): d
Selected partition 2
Partition 2 is deleted
Command (m for help): p
Disk /dev/vdb: 10.7 GB, 10737418240 bytes, 20971520 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xe503464f
Device Boot Start End Blocks Id System
Command (m for help): wq當誤刪除（即直接使用fdisk /dev/vdb刪除/dev/vdb1），出現removemissing時，處理方法爲：
vgreduce vgo –removemissing –force