Centos 7.4 服务器配置LVM（逻辑卷管理）

本章Blog相关知识点：LVM是
Logical Volume Manager(逻辑卷管理)的简写，它是Linux环境下对磁盘分区进行管理的一种机制，LVM是建立在硬盘和
分区之上的一个逻辑层，来提高磁盘分区管理的灵活性。LVM将若干个磁盘分区连接为一个整块的卷组
（volumegroup），形成一个存储池。管理员可以在卷组上随意创建逻辑卷组（logicalvolumes），并进一步在逻辑卷组上创建文件系
统。
与传统的磁盘与分区相比，LVM为计算机提供了更高层次的磁盘存储。它使系统管理员可以更方便的为应用与用户分配存储空间。在LVM管理下的存储卷可以按需要随时改变大小与移除(可能需对文件系统工具进行升级)。 LVM是在磁盘分区和文件系统之间添加的一个逻辑层，来为文件系统屏蔽下层磁盘分区布局，提供一个抽象的盘卷，在盘卷上建立文件系统。
逻辑卷管理概念：
物理卷(physical
volume)——物理卷就是指硬盘分区或从逻辑上与磁盘分区具有同样功能的设备(如RAID)，是LVM的基本存储逻辑块。但和基本的物理存储介质(如分区,磁盘等)比较, 却包含有与LVM相关的管理参数。
卷组(Volume
Group)——LVM卷组类似于非LVM系统中的物理硬盘，其由物理卷PV组成。可以在卷组上创建一个或多个"LV分区"(逻辑卷)，VG卷组由一个或多个物理卷PV组成。
逻辑卷(logical
volume)——LVM的逻辑卷类似于非LVM系统中的硬盘分区，在逻辑卷之上可以建立文件系统（比如/home或者/usr等）。
PE(physical
extent)——每一个物理卷被划分为称为PE(Physical
Extents)的基本单元，具有唯一编号的PE是可以被LVM寻址的最小单元。PE的大小是可配置的，默认为4MB。
LE(logical
extent)——逻辑卷也被划分为被称为LE(Logical Extents) 的可被寻址的基本单位。在同一个卷组中，LE的大小和PE是相同的，并且一一对应。
如下图所示PV、VG、LV三者关系：



设备文件名： /dev/卷组名/逻辑卷名 或 /dev/mapper/卷组名-逻辑卷名
物理卷管理命令：pv
pvcreate(创建pv), pvremove(移除pv), pvmove(移除卷内数据), pvscan(显示所有的pv卷), pvs(查看pv卷简要信息), pvdisplay (看pv卷详细信息)卷组管理命令：vgvgcreate(创建vg), vgremove(移除vg), vgs(查看vg卷简要信息), vgdisplay (查看vg卷详细信息), vgextend(扩展vg卷组), vgreduce(缩减vg卷组), vgrename (改名)# vgcreate -s PE_size 指定PE的大小 ,默认是4M
逻辑卷的管理命令：lv
lvcreate, lvremove, lvs, lvdisplay , lvextend(扩展lv卷组) , lvreduce(缩减lv卷组)
# lvcreate 创建lv逻辑卷 -n 指定lv名称 -L 逻辑卷大小 -s 创建快照 -p 指定模式# lvextend 扩展lv大小 -L [+] 5G 扩展[了]到5G获取以上命令帮助方法： # command -h ，例： #lvcreate -h

配置管理LVM实验（逻辑卷管理）系统环境：
系统：Centos 7.4 最小化安装
LVM管理工具：lvm2-2.02.171-8.el7.x86_64
磁盘分区：挂载/dev/sdb 、/dev/sdc 、/dev/sdd、/dev/sde 、/dev/sdf、 /dev/sdg 共6块磁盘
实验目的：
1、通过LVM管理工具，分别创建pv、vg 和lvm。
2、模拟扩展和缩减LV，模拟扩展或缩减VG
3、创建lv快照
4、卸载LVM，删除LVM
实验步骤：

[b]一、设置磁盘（虚拟机中增加6块10G磁盘），安装LVM 管理工具。[/b]
1、在Vmware 虚拟机中，增加6块磁盘 。




2、查看系统版本，验证lvm*管理工具是否安装 并查看磁盘信息

[root@study ~]# cat /etc/redhat-release
CentOS Linux release 7.4.1708 (Core)
[root@study ~]# rpm -qa |grep lvm*
lvm2-libs-2.02.171-8.el7.x86_64
lvm2-2.02.171-8.el7.x86_64
[root@study ~]# fdisk -l | grep "^Disk./dev"
Disk /dev/sda: 128.8 GB, 128849018880 bytes, 251658240 sectors
Disk /dev/sdb: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sdc: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sdd: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sde: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sdf: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/sdg: 10.7 GB, 10737418240 bytes, 20971520 sectors
Disk /dev/mapper/VG-root: 16.1 GB, 16106127360 bytes, 31457280 sectors
Disk /dev/mapper/VG-home: 21.5 GB, 21474836480 bytes, 41943040 sectors
Disk /dev/mapper/VG-var: 10.7 GB, 10737418240 bytes, 20971520 sectors

二、对增加的磁盘进行分区并修改分区类型为8e（Linux LVM），并验证分区结果

[root@study ~]# echo 'n
> p
> 1
>
>
> t
> 8e
> w '|fdisk /dev/sdb     ## 为/dev/sdb磁盘创建分区1 ，分配分区大小为磁盘总空间。并调整类型为8e（LVM）
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.

Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0x3bb09eb9.

Command (m for help): Partition type:
p   primary (0 primary, 0 extended, 4 free)
e   extended
Select (default p): Partition number (1-4, default 1): First sector (2048-20971519, default 2048): Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-20971519, default 20971519): Using default value 20971519
Partition 1 of type Linux and of size 10 GiB is set

Command (m for help): Selected partition 1
Hex code (type L to list all codes): Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@study ~]...   ## 以同样的命令方式对其他5块磁盘进行操作
[root@study ~]# fdisk -l | grep "LVM$"  ## 验证磁盘分区结果
/dev/sda3        12584960   251658239   119536640   8e  Linux LVM
/dev/sdb1            2048    20971519    10484736   8e  Linux LVM
/dev/sdc1            2048    20971519    10484736   8e  Linux LVM
/dev/sdd1            2048    20971519    10484736   8e  Linux LVM
/dev/sde1            2048    20971519    10484736   8e  Linux LVM
/dev/sdf1            2048    20971519    10484736   8e  Linux LVM
/dev/sdg1            2048    20971519    10484736   8e  Linux LVM
[root@study ~]# reboot   ## 内核重读磁盘分区
[root@study ~]# cat /proc/partitions  | grep "1$"    ##验证内核是否加载了磁盘分区
8        1    2097152 sda1
8       17   10484736 sdb1
8       33   10484736 sdc1
8       49   10484736 sdd1
8       65   10484736 sde1
8       81   10484736 sdf1
8       97   10484736 sdg1

三、创建PV 物理卷

[root@study ~]# pvcreate /dev/sd{b..e}1
Physical volume "/dev/sdb1" successfully created.
Physical volume "/dev/sdc1" successfully created.
Physical volume "/dev/sdd1" successfully created.
Physical volume "/dev/sde1" successfully created.
[root@study ~]# pvs
PV         VG Fmt  Attr PSize    PFree
/dev/sda3  VG lvm2 a--  <114.00g <69.00g
/dev/sdb1     lvm2 ---   <10.00g <10.00g
/dev/sdc1     lvm2 ---   <10.00g <10.00g
/dev/sdd1     lvm2 ---   <10.00g <10.00g
/dev/sde1     lvm2 ---   <10.00g <10.00g
[root@study ~]# pvscan
PV /dev/sda3   VG VG              lvm2 [<114.00 GiB / <69.00 GiB free]
PV /dev/sdd1                      lvm2 [<10.00 GiB]
PV /dev/sde1                      lvm2 [<10.00 GiB]
PV /dev/sdc1                      lvm2 [<10.00 GiB]
PV /dev/sdb1                      lvm2 [<10.00 GiB]
Total: 5 [153.99 GiB] / in use: 1 [<114.00 GiB] / in no VG: 4 [<40.00 GiB]
[root@study ~]# pvdisplay
--- Physical volume ---
PV Name               /dev/sda3
VG Name               VG
PV Size               <114.00 GiB / not usable 3.00 MiB
Allocatable           yes
PE Size               4.00 MiB
Total PE              29183
Free PE               17663
Allocated PE          11520
PV UUID               2Ksdp4-23Ia-jnvA-BeO4-31O2-chlO-I2CQTc

"/dev/sdd1" is a new physical volume of "<10.00 GiB"
--- NEW Physical volume ---
PV Name               /dev/sdd1
VG Name
PV Size               <10.00 GiB
Allocatable           NO
PE Size               0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               MjYIgP-smsp-E72x-4eOQ-kQpG-vIAA-axaKXp
...

说明：#pvcreate /dev/sd{b..g}1 创建pv物理卷；
# pvdisplay | pvs | pvscan 查看pv状态信息
PV Name, 物理卷名；
VG Name, 所属卷组名；
PV Size，物理卷大小；
PV UUID ，PV UUID 号

四、创建myvg 卷组 ,指定PE大小为16M

[root@study ~]# vgcreate /dev/myvg -s 16M /dev/sd{b..e}1
Volume group "myvg" successfully created
[root@study dev]# vgs
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   4   0   0 wz--n-  <39.94g <39.94g
[root@study dev]# vgscan
Reading volume groups from cache.
Found volume group "VG" using metadata type lvm2
Found volume group "myvg" using metadata type lvm2
[root@study dev]# pvs
PV         VG   Fmt  Attr PSize    PFree
/dev/sda3  VG   lvm2 a--  <114.00g <69.00g
/dev/sdb1  myvg lvm2 a--     9.98g   9.98g
/dev/sdc1  myvg lvm2 a--     9.98g   9.98g
/dev/sdd1  myvg lvm2 a--     9.98g   9.98g
/dev/sde1  myvg lvm2 a--     9.98g   9.98g
[root@study dev]# pvdisplay

--- Physical volume ---
PV Name               /dev/sdb1
VG Name               myvg
PV Size               <10.00 GiB / not usable 15.00 MiB
Allocatable           yes
PE Size               16.00 MiB
Total PE              639
Free PE               639
Allocated PE          0
PV UUID               ZbZyCp-MiC8-Nnha-npKK-aVsr-ahTB-CIs2ok
...
[root@study dev]# vgdisplay

--- Volume group ---
VG Name               myvg
System ID
Format                lvm2
Metadata Areas        4
Metadata Sequence No  1
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                0
Open LV               0
Max PV                0
Cur PV                4
Act PV                4
VG Size               <39.94 GiB
PE Size               16.00 MiB
Total PE              2556
Alloc PE / Size       0 / 0
Free  PE / Size       2556 / <39.94 GiB
VG UUID               hgiXN3-e8Z1-NLL2-tJ2q-hVtD-t2BO-i7uafQ

说明：#vgcreate myvg -s 16M /dev/sd{b..e}1 创建myvg1卷组，并指定PE大小为16M；
# pvdisplay | pvs | pvscan 查看pv状态信息
PE Size ，PE的大小16M，默认为4MB
Total PE，PE的总数量
Free PE / Size ，空闲PE的数量及大小
# vgdisplay | vgs |vgscan 查看vg状态信息
VG name，VG名字

VG Size ，VG容量

五、创建mylv 逻辑卷并查看pv，vg及lv状态， 格式化lv逻辑卷并实现开机挂载

[root@study dev]# lvs
LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
home VG   -wi-ao---- 20.00g
root VG   -wi-ao---- 15.00g
var  VG   -wi-ao---- 10.00g
mylv myvg -wi-a----- 20.00g
[root@study dev]# lvscan
ACTIVE            '/dev/VG/root' [15.00 GiB] inherit
ACTIVE            '/dev/VG/home' [20.00 GiB] inherit
ACTIVE            '/dev/VG/var'  [10.00 GiB] inherit
ACTIVE            '/dev/myvg/mylv' [20.00 GiB] inherit
[root@study dev]# lvdisplay
...
--- Logical volume ---
LV Path                /dev/myvg/mylv
LV Name                mylv
VG Name                myvg
LV UUID                7aaK0H-sUpW-KYBL-awJl-1Jr9-Sewp-trSQi0
LV Write Access        read/write
LV Creation host, time study.itwish.cn, 2018-02-04 16:33:22 +0800
LV Status              available
# open                 0
LV Size                20.00 GiB
Current LE             1280
Segments               3
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:3
[root@study dev]# pvs
PV         VG   Fmt  Attr PSize    PFree
/dev/sda3  VG   lvm2 a--  <114.00g <69.00g
/dev/sdb1  myvg lvm2 a--     9.98g      0
/dev/sdc1  myvg lvm2 a--     9.98g      0
/dev/sdd1  myvg lvm2 a--     9.98g   9.95g
/dev/sde1  myvg lvm2 a--     9.98g   9.98g
[root@study dev]# pvscan
PV /dev/sda3   VG VG              lvm2 [<114.00 GiB / <69.00 GiB free]
PV /dev/sdb1   VG myvg            lvm2 [9.98 GiB / 0    free]
PV /dev/sdc1   VG myvg            lvm2 [9.98 GiB / 0    free]
PV /dev/sdd1   VG myvg            lvm2 [9.98 GiB / 9.95 GiB free]
PV /dev/sde1   VG myvg            lvm2 [9.98 GiB / 9.98 GiB free]
Total: 5 [153.93 GiB] / in use: 5 [153.93 GiB] / in no VG: 0 [0   ]
[root@study dev]# vgs
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   4   1   0 wz--n-  <39.94g <19.94g
[root@study dev]# vgscan
Reading volume groups from cache.
Found volume group "VG" using metadata type lvm2
Found volume group "myvg" using metadata type lvm2
[root@study dev]# vgdisplay
...
--- Volume group ---
VG Name               myvg
System ID
Format                lvm2
Metadata Areas        4
Metadata Sequence No  2
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                1
Open LV               0
Max PV                0
Cur PV                4
Act PV                4
VG Size               <39.94 GiB
PE Size               16.00 MiB
Total PE              2556
Alloc PE / Size       1280 / 20.00 GiB
Free  PE / Size       1276 / <19.94 GiB
VG UUID               hgiXN3-e8Z1-NLL2-tJ2q-hVtD-t2BO-i7uafQ
[root@study dev]# ls /dev/mapper/
control  myvg-mylv  VG-home  VG-root  VG-var
[root@study dev]# ls /dev/myvg/
mylv
[root@study dev]# mke2fs -t ext4 -m 2 -L mylvdata /dev/mapper/myvg-mylv  ##创建文件系统
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=mylvdata
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5242880 blocks
104857 blocks (2.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

[root@study dev]# mount /dev/mapper/myvg-mylv /mylv/    ##挂载
[root@study dev]# ls /mylv/
lost+found
[root@study dev]# mount | grep "^/dev"
/dev/mapper/VG-root on / type ext4 (rw,relatime,seclabel,data=ordered)
/dev/sda1 on /boot type ext4 (rw,relatime,seclabel,data=ordered)
/dev/mapper/VG-home on /home type ext4 (rw,relatime,seclabel,data=ordered)
/dev/mapper/VG-var on /var type ext4 (rw,relatime,seclabel,data=ordered)
/dev/mapper/myvg-mylv on /mylv type ext4 (rw,relatime,seclabel,data=ordered)
[root@study dev]# df -h | grep "^/dev"
/dev/mapper/VG-root     15G  1.2G   13G   9% /
/dev/sda1              2.0G  116M  1.7G   7% /boot
/dev/mapper/VG-home     20G   45M   19G   1% /home
/dev/mapper/VG-var     9.8G  200M  9.1G   3% /var
/dev/mapper/myvg-mylv   20G   45M   20G   1% /mylv
[root@study dev]# vi /etc/fstab   ## 配置开机自动挂载
#
# /etc/fstab
# Created by anaconda on Sun Jan 28 12:27:18 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/VG-root     /                       ext4    defaults        1 1
UUID=085b953d-5803-45df-b9d9-dc0ff7f92a3d /boot                   ext4    defa
ults        1 2
/dev/mapper/VG-home     /home                   ext4    defaults        1 2
/dev/mapper/VG-var      /var                    ext4    defaults        1 2
UUID=4169cca6-5a09-46fe-a2a7-64eba563b00a swap                    swap    defa
ults        0 0
/dev/myvg/mylv         /mylv                    ext4    defaults         0 2

说明：#lvcreate -n mylv -L 20G myvg 从myvg 卷组中分配20G并创建mylv逻辑卷；-n 指定LVM名字 ，-L 分配容量大小
# lvdisplay | lvs | lvscan 查看lv状态信息
LV Path ，LV的路径
LV Name， LV的名字VG Name所属的VG
LV Size ， LV的大小

六、扩展或缩减mylv 逻辑卷
LVM最大的优势是可以对磁盘进行动态管理，而且不会丢失现有的数据。
1、扩展LVM的思路：

先确定扩展的大小，并确保所属的卷组有足够的剩余空间
扩展物理边界 ，卸载逻辑卷umount ；
通过命令e2fsck检查lv逻辑卷 ；# lvextend -L 【+】Size /path/to/lv_device
扩展逻辑边界# resize2fs /path/to/lv_device Size

[root@study ~]# cp -af /boot/ /mylv/
[root@study ~]# ls /mylv/
boot  lost+found
[root@study ~]# lvs
LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
...
mylv myvg -wi-a----- 20.00g
[root@study ~]# df -lh
..
/dev/mapper/myvg-mylv   20G  154M   19G   1% /mylv
...
[root@study ~]# vgs      ##确保剩余空间 ，扩展的大小必须小于卷组剩余空间大小，myvg剩余vg大小为19.94G
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   4   1   0 wz--n-  <39.94g <19.94g
[root@study ~]# umount /mylv/   ##卸载磁盘分区/mylv/
[root@study ~]# e2fsck -fy /dev/mapper/myvg-mylv   ##检查并修复磁盘
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
mylvdata: 338/1310720 files (0.3% non-contiguous), 154377/5242880 blocks
[root@study ~]# lvextend -L +5G /dev/mapper/myvg-mylv   ##为LV逻辑卷扩展增加5G空间
Size of logical volume myvg/mylv changed from 20.00 GiB (1280 extents) to 25.00 GiB (1600 extents).
Logical volume myvg/mylv successfully resized.
[root@study ~]# lvs   ##lv卷增加到25G空间
LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
...
mylv myvg -wi-ao---- 25.00g
[root@study ~]# resize2fs /dev/mapper/myvg-mylv   ##为/dev/mapper/myvg-mylv扩展逻辑边界
resize2fs 1.42.9 (28-Dec-2013)
Filesystem at /dev/mapper/myvg-mylv is mounted on /mylv; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 4
The filesystem on /dev/mapper/myvg-mylv is now 6553600 blocks long.
[root@study ~]# df -lh    ##查看磁盘大小
Filesystem             Size  Used Avail Use% Mounted on
...
/dev/mapper/myvg-mylv   25G  154M   24G   1% /mylv
[root@study ~]# ls /mylv/   ##确认磁盘数据存在
boot  lost+found

2、缩减LVM思路：

卸载逻辑卷umount ；

通过命令e2fsck检查lv逻辑卷 ；
缩减LVM逻辑卷逻辑边界（确保缩减后的空间大小依然能存储原有的所有数据）；
# resize2fs /path/to/lv_device Size
缩减物理边界# lvreduce -L
[-] size /path/to/lv_devcie
重新挂载

[root@study ~]# lvs   ##确认lv卷空间大小
LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
...
mylv myvg -wi-ao---- 25.00g
[root@study ~]# df -lh    ##查看磁盘大小
Filesystem             Size  Used Avail Use% Mounted on
...
/dev/mapper/myvg-mylv   25G  154M   24G   1% /mylv
[root@study ~]# umount /dev/myvg/mylv
[root@study ~]# e2fsck -fy /dev/mapper/myvg-mylv
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
mylvdata: 338/1638400 files (0.3% non-contiguous), 174937/6553600 blocks
[root@study ~]# resize2fs /dev/mapper/myvg-mylv 15G   ##缩减逻辑边界空间大小为15G
resize2fs 1.42.9 (28-Dec-2013)
Resizing the filesystem on /dev/mapper/myvg-mylv to 3932160 (4k) blocks.
The filesystem on /dev/mapper/myvg-mylv is now 3932160 blocks long.
[root@study ~]# lvreduce -L 15G /dev/mapper/myvg-mylv  ##缩减lv卷大小为15G
WARNING: Reducing active logical volume to 15.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce myvg/mylv? [y/n]: y
Size of logical volume myvg/mylv changed from 25.00 GiB (1600 extents) to 15.00 GiB (960 extents).
Logical volume myvg/mylv successfully resized.
[root@study ~]# mount /dev/mapper/myvg-mylv /mylv/
[root@study ~]# df -lh
Filesystem             Size  Used Avail Use% Mounted on
...
/dev/mapper/myvg-mylv   15G  150M   15G   2% /mylv
[root@study ~]# lvs
LV   VG   Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
...
mylv myvg -wi-ao---- 15.00g

说明：# e2fsck -fy /dev/mapper/myvg-mylv 强制检查文件系统； -f 强制
#lvreduce -L 15G /dev/myvg-mylv 分配到mylv逻辑卷大小为5G； -L 分配容量大小

# lvextend -L +5G /dev/mapper/myvg-mylv 扩展5G容量分配到mylv1逻辑卷； -L 分配容量大小 +5G 扩展5G
# resize2fs /dev/mapper/myvg-mylv 扩展文件系统与逻辑卷大小一致

# resize2fs /dev/mapper/myvg-mylv 15G 缩减逻辑边界空间大小为15G

七、扩展或缩减myvg 卷组
1、扩展vg卷组思路
准备要添加的物理卷
添加物理卷至卷组中# vgextend vg_name /path/to/pv_devcie

[root@study ~]# pvcreate /dev/sd{f,g}1
Physical volume "/dev/sdf1" successfully created.
Physical volume "/dev/sdg1" successfully created.
[root@study ~]# vgs
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   4   1   0 wz--n-  <39.94g <24.94g
[root@study ~]# vgextend myvg /dev/sd{g,f}1  ##扩展2个磁盘分区到myvg卷组
Volume group "myvg" successfully extended
[root@study ~]# vgs    ## 卷组大小增加20G空间
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   6   1   0 wz--n-  <59.91g <44.91g

2、缩减vg卷组思路
去顶要移除的物理卷的总空间大小，要小于vg当前的空闲空间大小
将要移除的物理卷上的数据移动至其他PV# pvmove /path/to/pv_device
缩减vg# vgreduce vg_name /path/to/pv_device

[root@study ~]# vgs  ##磁盘卷组空闲free空间为44.91G
VG   #PV #LV #SN Attr   VSize    VFree
VG     1   3   0 wz--n- <114.00g <69.00g
myvg   6   1   0 wz--n-  <59.91g <44.91g
[root@study ~]# pvs   ## 确认分区/dev/sdb1 和分区/dev/sdc1分区被使用，存有数据
PV         VG   Fmt  Attr PSize    PFree
/dev/sda3  VG   lvm2 a--  <114.00g <69.00g
/dev/sdb1  myvg lvm2 a--     9.98g      0
/dev/sdc1  myvg lvm2 a--     9.98g  <4.97g
/dev/sdd1  myvg lvm2 a--     9.98g   9.98g
/dev/sde1  myvg lvm2 a--     9.98g   9.98g
/dev/sdf1  myvg lvm2 a--     9.98g   9.98g
/dev/sdg1  myvg lvm2 a--     9.98g   9.98g
[root@study ~]# pvmove /dev/sdf1   ##转移数据
No data to move for myvg
[root@study ~]# pvmove /dev/sdg1
No data to move for myvg
[root@study ~]# vgreduce myvg /dev/sd{f,g}1   ##缩减vg卷组，删除分区/dev/sdf1 和分区/dev/sdg1
Removed "/dev/sdg1" from volume group "myvg"
Removed "/dev/sdf1" from volume group "myvg"
[root@study ~]# pvremove /dev/sd{g,f}1   ##删除pv卷
Labels on physical volume "/dev/sdg1" successfully wiped.
Labels on physical volume "/dev/sdf1" successfully wiped.

说明：#vgextend myvg /dev/sd{f,g}1 扩展分区/dev/sdf1和分区/dev/sdg1到vg卷组

#pvmove /dev/sdg1 将分区/dev/sdg1中的数据转移到其他分区

# vgreduce myvg /dev/sd{f,g}1 在myvg卷组中缩减删除pv分区/dev/sdg1，/dev/sdf1

# pvremove /dev/sd{g，f}1 删除pv卷
八、创建LVM快照卷，完成数据备份及还原
1、实现思路

创建快照# lvcreate -s -L size -n Name -p r /path/to/original_lv_device
挂载# mount /dev/mapper/myvg_name /media 例 # mount /dev/mapper/myvg-test--snap /media/
把挂载数据备份tar -zcf /root/media.tar.gz /media/*
卸载快照卷 ，移除快照卷lvremove /dev/myvg/test-snap
模拟删除lv数据，通过快照数据进行还原

[root@study ~]# lvcreate -s -L 10G -n mylvspare  -p r /dev/mapper/myvg-mylv
Using default stripesize 64.00 KiB.
Logical volume "mylvspare" created.
[root@study ~]# mount /dev/mapper/myvg-mylvspare /media/
mount: /dev/mapper/myvg-mylvspare is write-protected, mounting read-only
[root@study ~]# ls /media/
boot  lost+found
[root@study ~]# tar -zcf /root/spare.tar.gz /media/*
tar: Removing leading `/' from member names
[root@study ~]# ls -lh
total 102M
-rw-------. 1 root root 1.8K Jan 28 12:33 anaconda-ks.cfg
drwxrwxr-x. 2 root root  36K Sep  5 21:38 Packages
-rw-r--r--. 1 root root 102M Feb  4 18:11 spare.tar.gz
[root@study ~]# umount /dev/mapper/myvg-mylvspare
[root@study ~]# lvremove /dev/mapper/myvg-mylvspare
Do you really want to remove active logical volume myvg/mylvspare? [y/n]: y
Logical volume "mylvspare" successfully removed
[root@study ~]# rm -rf /mylv/boot/   ##模拟删除LV卷中数据，通过备份的快照数据进行还原
[root@study mylv]# cd /root/
[root@study ~]# ls
anaconda-ks.cfg  Packages  spare.tar.gz
[root@study ~]# tar -zxf spare.tar.gz
[root@study ~]# ls
anaconda-ks.cfg  media  Packages  spare.tar.gz
[root@study mylv]# cp -af  /root/media/* /mylv/
[root@study mylv]# ls     ## 通过快照数据进行数据还原
config-3.10.0-693.el7.x86_64
efi
grub
grub2
initramfs-0-rescue-aa42d80ce1774acf8f5de007d85e5ef1.img
initramfs-3.10.0-693.el7.x86_64.img
initramfs-3.10.0-693.el7.x86_64kdump.img
initrd-plymouth.img
lost+found
mylv
symvers-3.10.0-693.el7.x86_64.gz
System.map-3.10.0-693.el7.x86_64
vmlinuz-0-rescue-aa42d80ce1774acf8f5de007d85e5ef1
vmlinuz-3.10.0-693.el7.x86_64

九、卸载删除lVM

[root@study media]# umount  /dev/mapper/myvg-mylv
[root@study media]# lvremove /dev/mapper/myvg-mylv
Do you really want to remove active logical volume myvg/mylv? [y/n]: y
Logical volume "mylv" successfully removed
[root@study media]# vgremove myvg
Volume group "myvg" successfully removed
[root@study media]# pvremove /dev/sd{b..e}1
Labels on physical volume "/dev/sdb1" successfully wiped.
Labels on physical volume "/dev/sdc1" successfully wiped.
Labels on physical volume "/dev/sdd1" successfully wiped.
Labels on physical volume "/dev/sde1" successfully wiped.

至此 ，整体部署配置LVM实验完成 。