简介
逻辑卷管理LVM是一个多才多艺的硬盘系统工具。无论在Linux或者其他类似的系统，都是非常的好用。传统分区使用固定大小分区，重新调整大小十分麻烦。但是，LVM可以创建和管理“逻辑”卷，而不是直接使用物理硬盘。可以让管理员弹性的管理逻辑卷的扩大缩小，操作简单，而不损坏已存储的数据。可以随意将新的硬盘添加到LVM，以直接扩展已经存在的逻辑卷。LVM并不需要重启就可以让内核知道分区的存在。

LVM使用分层结构，如下图所示。
Linux LVM系列（一）lvm使用
首先是实际的物理磁盘及其划分的分区和其上的物理卷（PV）。一个或多个物理卷可以用来创建卷组（VG）。然后基于卷组可以创建逻辑卷（LV）。只要在卷组中有可用空间，就可以随心所欲的创建逻辑卷。文件系统就是在逻辑卷上创建的，然后可以在操作系统挂载和访问
磁盘分区
1、首先使用fdisk增加的磁盘分区

#fdisk /dev/sdb 
Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0xff3a8918

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048     4196351     2097152   8e  Linux LVM
/dev/sdb2         4196352     8390655     2097152   8e  Linux LVM
/dev/sdb3         8390656    12584959     2097152   8e  Linux LVM

迅速创建扩展分区，并划分3个逻辑分区

Command (m for help): n
Partition type:
   p   primary (3 primary, 0 extended, 1 free)
   e   extended
Select (default e): e
Selected partition 4
First sector (12584960-41943039, default 12584960): 
Using default value 12584960
Last sector, +sectors or +size{K,M,G} (12584960-41943039, default 41943039): 
Using default value 41943039
Partition 4 of type Extended and of size 14 GiB is set

Command (m for help): n
All primary partitions are in use
Adding logical partition 5
First sector (12587008-41943039, default 12587008): 
Using default value 12587008
Last sector, +sectors or +size{K,M,G} (12587008-41943039, default 41943039): +2G
Partition 5 of type Linux and of size 2 GiB is set

Command (m for help): n
All primary partitions are in use
Adding logical partition 6
First sector (16783360-41943039, default 16783360): 
Using default value 16783360
Last sector, +sectors or +size{K,M,G} (16783360-41943039, default 41943039): +2G
Partition 6 of type Linux and of size 2 GiB is set

Command (m for help): n  
All primary partitions are in use
Adding logical partition 7
First sector (20979712-41943039, default 20979712): 
Using default value 20979712
Last sector, +sectors or +size{K,M,G} (20979712-41943039, default 41943039): +2G
Partition 7 of type Linux and of size 2 GiB is set

Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0xff3a8918

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048     4196351     2097152   8e  Linux LVM
/dev/sdb2         4196352     8390655     2097152   8e  Linux LVM
/dev/sdb3         8390656    12584959     2097152   8e  Linux LVM
/dev/sdb4        12584960    41943039    14679040    5  Extended
/dev/sdb5        12587008    16781311     2097152   83  Linux
/dev/sdb6        16783360    20977663     2097152   83  Linux
/dev/sdb7        20979712    25174015     2097152   83  Linux

2、t更改分区文件系统的ID为8E，并w保存操作

Command (m for help): t
Partition number (1-7, default 7): 5
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): t
Partition number (1-7, default 7): 6
Hex code (type L to list all codes): 8e  
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): t
Partition number (1-7, default 7): 
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'

Command (m for help): p

Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 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: 0xff3a8918

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1            2048     4196351     2097152   8e  Linux LVM
/dev/sdb2         4196352     8390655     2097152   8e  Linux LVM
/dev/sdb3         8390656    12584959     2097152   8e  Linux LVM
/dev/sdb4        12584960    41943039    14679040    5  Extended
/dev/sdb5        12587008    16781311     2097152   8e  Linux LVM
/dev/sdb6        16783360    20977663     2097152   8e  Linux LVM
/dev/sdb7        20979712    25174015     2097152   8e  Linux LVM

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

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

3、为了能快速的加载新分区，我们使用partprobe命令手动更新

[root@aiker01 ~]# partprobe
[root@aiker01 ~]# ll /dev/sdb
sdb   sdb1  sdb2  sdb3  sdb4  sdb5  sdb6  sdb7

4、创建物理卷PV

[root@aiker01 ~]# pvcreate /dev/sdb5 /dev/sdb6 /dev/sdb7
  Physical volume "/dev/sdb5" successfully created.
  Physical volume "/dev/sdb6" successfully created.
  Physical volume "/dev/sdb7" successfully created.

列出刚才创建的物理卷，新创建的物理卷都会带“--- NEW Physical volume ---”

[root@aiker01 ~]# pvdisplay /dev/sdb[5-7]
  "/dev/sdb7" is a new physical volume of "2.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb7
  VG Name               
  PV Size               2.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               XegRtK-Fr4V-AfJ2-QVxu-hOo2-dGE8-HR2dox

  "/dev/sdb6" is a new physical volume of "2.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb6
  VG Name               
  PV Size               2.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               p6WjVw-X3th-BZVW-UfI9-nCIo-uLPg-uO5pUW

  "/dev/sdb5" is a new physical volume of "2.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb5
  VG Name               
  PV Size               2.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               KCPzgS-O43B-CFua-xSUn-fdCX-emSS-WHWQBG

pvs命令可以列出物理卷的使用列表，物理卷大小，使用情况，剩余的物理卷大小

[root@aiker01 ~]# pvs
  PV         VG  Fmt  Attr PSize   PFree
  /dev/sda3  cl  lvm2 a--  <19.51g 4.00m
  /dev/sdb1  vg1 lvm2 a--   <2.00g    0 
  /dev/sdb2  vg1 lvm2 a--   <2.00g    0 
  /dev/sdb3  vg1 lvm2 a--   <2.00g    0 
  /dev/sdb5      lvm2 ---    2.00g 2.00g
  /dev/sdb6      lvm2 ---    2.00g 2.00g
  /dev/sdb7      lvm2 ---    2.00g 2.00g

创建卷组VGS
先查看现有的卷组

[root@aiker01 ~]# vgs
  VG  #PV #LV #SN Attr   VSize   VFree
  cl    1   4   0 wz--n- <19.51g 4.00m
  vg1   3   1   0 wz--n-  <5.99g    0 

[root@aiker01 ~]# vgcreate vg2 /dev/sdb[5-6]
  Volume group "vg2" successfully created
[root@aiker01 ~]# vgdisplay vg2 #列出刚才创建的卷组详情
   --- Volume group ---
  VG Name               vg2
  System ID             
  Format                lvm2
  Metadata Areas        2
  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                2
  Act PV                2
  VG Size               3.99 GiB
  PE Size               4.00 MiB
  Total PE              1022
  Alloc PE / Size       0 / 0   
  Free  PE / Size       1022 / 3.99 GiB
  VG UUID               0yIJqM-O6HU-c7yO-VeBZ-AWz3-WiJQ-cUSM1i

[root@aiker01 ~]# vgs
  VG  #PV #LV #SN Attr   VSize   VFree
  cl    1   4   0 wz--n- <19.51g 4.00m
  vg1   3   1   0 wz--n-  <5.99g    0 
  vg2   2   0   0 wz--n-   3.99g 3.99g

创建逻辑卷LVS

[```root@aiker01 ~]# lvcreate -l 1022 -n lv2 vg2 #-l 按pe,-L按size
Logical volume "lv2" created.


**格式化逻辑卷**

[root@aiker01 ~]# mkfs.ext4 /dev/vg2/lv2 
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
261632 inodes, 1046528 blocks
52326 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1071644672
32 block groups
32768 blocks per group, 32768 fragments per group
8176 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done 

[root@aiker01 ~]# lvs
  LV   VG  Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  home cl  -wi-ao----  4.00g                                                    
  root cl  -wi-ao----  8.57g                                                    
  swap cl  -wi-ao----  4.00g                                                    
  var  cl  -wi-ao---- <2.93g                                                    
  lv1  vg1 -wi-ao---- <5.99g                                                    
  lv2  vg2 -wi-a-----  3.99g                                                    
[root@aiker01 ~]# lsblk -f
NAME        FSTYPE      LABEL UUID                                   MOUNTPOINT
sda                                                                  
├─sda1                                                               
├─sda2      xfs               460aa503-2017-41c1-a406-c94f8b1097b7   /boot
└─sda3      LVM2_member       KzLxC5-B3g0-qvz5-4Bsf-Neaq-y3f1-cmRV0I 
  ├─cl-root xfs               16cc098f-10c5-4b7d-9a3a-cfd0289a0e12   /
  ├─cl-swap swap              542d997a-3a61-4e10-afe5-f4f96277eba9   [SWAP]
  ├─cl-var  xfs               2b8c9632-31ea-4299-9cb3-aa8d6d9c030e   /var
  └─cl-home xfs               b7a246f3-746e-49e4-bab0-4def83faaa26   /home
sdb                                                                  
├─sdb1      LVM2_member       osUKLK-uhqg-5owr-qicf-m5Rj-NnxA-7kZOdb 
│ └─vg1-lv1 ext4              22c8fa37-a406-4d65-b853-1bb361296a7f   /mnt
├─sdb2      LVM2_member       1lNxWq-1jKg-mRfu-NJpO-8996-d5Nc-lpGfwu 
│ └─vg1-lv1 ext4              22c8fa37-a406-4d65-b853-1bb361296a7f   /mnt
├─sdb3      LVM2_member       CsatVM-Qjr6-OdZi-Z150-ToEk-Fwty-dScaIs 
│ └─vg1-lv1 ext4              22c8fa37-a406-4d65-b853-1bb361296a7f   /mnt
├─sdb4                                                               
├─sdb5      LVM2_member       KCPzgS-O43B-CFua-xSUn-fdCX-emSS-WHWQBG 
│ └─vg2-lv2 ext4              75ba0d5a-f0e5-4182-a543-d24c83843b3d   
├─sdb6      LVM2_member       p6WjVw-X3th-BZVW-UfI9-nCIo-uLPg-uO5pUW 
│ └─vg2-lv2 ext4              75ba0d5a-f0e5-4182-a543-d24c83843b3d   
└─sdb7      LVM2_member       XegRtK-Fr4V-AfJ2-QVxu-hOo2-dGE8-HR2dox 
sr0                                                                  
[root@aiker01 ~]# mkdir /data **#创建目录**
[root@aiker01 ~]# mount /dev/vg2/lv2 /data/** #挂载格式化后的逻辑卷**

[root@aiker01 ~]# df -hT** #查看文件系统的详情**
Filesystem          Type      Size  Used Avail Use% Mounted on
/dev/mapper/cl-root xfs       8.6G  5.3G  3.4G  62% /
devtmpfs            devtmpfs  2.4G     0  2.4G   0% /dev
tmpfs               tmpfs     2.4G     0  2.4G   0% /dev/shm
tmpfs               tmpfs     2.4G  8.7M  2.4G   1% /run
tmpfs               tmpfs     2.4G     0  2.4G   0% /sys/fs/cgroup
/dev/mapper/cl-home xfs       4.0G   33M  4.0G   1% /home
/dev/mapper/cl-var  xfs       3.0G  159M  2.8G   6% /var
/dev/sda2           xfs       497M  132M  366M  27% /boot
/dev/mapper/vg1-lv1 ext4      5.9G   16M  5.6G   1% /mnt
tmpfs               tmpfs     479M     0  479M   0% /run/user/0
/dev/mapper/vg2-lv2 ext4      3.9G   16M  3.7G   1% /data