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。
一. LVM基本命令
| 功能/命令 | 物理卷管理 | 卷组管理 | 逻辑卷管理 |
| 扫描 | pvscan | vgscan | lvscan |
| 建立 | pvcreate | vgcreate | lvcreate |
| 显示 | pvdisplay/pvs | vgdisplay/vgs | lvdisplay/lvs |
| 删除 | pvremove | vgremove | lvremove |
| 扩展 | vgextend | lvextend | |
| 缩小 | vgreduce | lvreduce |
二. LVM基本概念
1. 物理磁盘被格式化为PV, 空间被分为一个个PE(PE默认大小是4M）
2. 不同的PV被加入同一个VG,不同PV的PE全部进入VG的存储池
3. LV是基于PE创建，大小是PE的整数倍，组成LV的PE可能来自不同的PV
4. LV可以格式化后挂载使用
5. LV的扩充和增减就是增减组成该LV的PE的数量.其过程不会丢失原始数据
三. LVM的创建，查看和删除
1. 查看物理磁盘fdisk -l 或lsblk
[vic@localhost ~]$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 8G 0 disk ├─sda1 8:1 0 1G 0 part /boot └─sda2 8:2 0 7G 0 part ├─centos-root 253:0 0 6.2G 0 lvm / └─centos-swap 253:1 0 820M 0 lvm [SWAP] sdb 8:16 0 8G 0 disk sdc 8:32 0 8G 0 disk sdd 8:48 0 8G 0 disk sde 8:64 0 8G 0 disk sr0 11:0 1 1024M 0 rom
2. 将物理磁盘设备转换为物理卷
[vic@localhost ~]$ sudo pvcreate /dev/sdb /dev/sdc Physical volume "/dev/sdb" successfully created. Physical volume "/dev/sdc" successfully created. [vic@localhost ~]$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <7.00g 0 /dev/sdb lvm2 --- 8.00g 8.00g /dev/sdc lvm2 --- 8.00g 8.00g
3. 创建卷组，并将PV加入卷组中
[vic@localhost ~]$ sudo vgcreate linux-vli /dev/sdb /dev/sdc Volume group "linux-vli" successfully created [vic@localhost ~]$ sudo vgs VG #PV #LV #SN Attr VSize VFree centos 1 2 0 wz--n- <7.00g 0 linux-vli 2 0 0 wz--n- 15.99g 15.99g
4. 创建逻辑卷
[vic@localhost ~]$ sudo lvcreate -n sharelv -L 4G linux-vli Logical volume "sharelv" created. [vic@localhost ~]$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- <6.20g swap centos -wi-ao---- 820.00m sharelv linux-vli -wi-a----- 4.00g
5. 格式化逻辑卷创建文件系统
[vic@localhost ~]$ sudo mkfs.ext4 /dev/linux-vli/sharelv
6. 将格式化的逻辑卷挂载使用
[vic@localhost ~]$ sudo mkdir /sharelv [vic@localhost ~]$ sudo mount /dev/linux-vli/sharelv /sharelv/ [vic@localhost ~]$ df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 6.2G 1.4G 4.9G 22% / devtmpfs 484M 0 484M 0% /dev tmpfs 496M 0 496M 0% /dev/shm tmpfs 496M 6.9M 490M 2% /run tmpfs 496M 0 496M 0% /sys/fs/cgroup /dev/sda1 1014M 132M 883M 14% /boot tmpfs 100M 0 100M 0% /run/user/0 tmpfs 100M 0 100M 0% /run/user/1000 /dev/mapper/linux--vli-sharelv 3.9G 16M 3.6G 1% /sharelv
7. 删除LV --> 删除VG --> 删除物理卷
[vic@localhost ~]$ sudo umount /sharelv [vic@localhost ~]$ df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 6.2G 1.4G 4.9G 22% / devtmpfs 484M 0 484M 0% /dev tmpfs 496M 0 496M 0% /dev/shm tmpfs 496M 6.9M 490M 2% /run tmpfs 496M 0 496M 0% /sys/fs/cgroup /dev/sda1 1014M 132M 883M 14% /boot tmpfs 100M 0 100M 0% /run/user/0 tmpfs 100M 0 100M 0% /run/user/1000 [vic@localhost ~]$ sudo lvremove /dev/linux-vli/sharelv Do you really want to remove active logical volume linux-vli/sharelv? [y/n]: y Logical volume "sharelv" successfully removed [vic@localhost ~]$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- <6.20g swap centos -wi-ao---- 820.00m [vic@localhost ~]$ sudo vgremove linux-vli Volume group "linux-vli" successfully removed [vic@localhost ~]$ sudo vgs VG #PV #LV #SN Attr VSize VFree centos 1 2 0 wz--n- <7.00g 0 [vic@localhost ~]$ sudo pvremove /dev/sdb /dev/sdc Labels on physical volume "/dev/sdb" successfully wiped. Labels on physical volume "/dev/sdc" successfully wiped. [vic@localhost ~]$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <7.00g 0
四. LVM卷扩展
1. 查看VG的剩余空间
[vic@localhost ~]$ sudo vgdisplay --- Volume group --- VG Name linux-vli System ID Format lvm2 Metadata Areas 2 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 2 Act PV 2 VG Size 15.99 GiB PE Size 4.00 MiB Total PE 4094 Alloc PE / Size 1024 / 4.00 GiB Free PE / Size 3070 / 11.99 GiB VG UUID 0sJQDx-2Ijp-K0in-jdTs-1fvG-FW2n-n2dXND
2. 扩充逻辑卷
[vic@localhost ~]$ sudo lvextend -L +3G /dev/linux-vli/sharelv Size of logical volume linux-vli/sharelv changed from 4.00 GiB (1024 extents) to 7.00 GiB (1792 extents). Logical volume linux-vli/sharelv successfully resized. [vic@localhost ~]$ sudo lvdisplay --- Logical volume --- LV Path /dev/linux-vli/sharelv LV Name sharelv VG Name linux-vli LV UUID bS4J9e-ggqT-RKXG-m4Gg-lUDW-dFkg-Y85ChG LV Write Access read/write LV Creation host, time localhost.localdomain, 2019-05-07 12:42:09 +0800 LV Status available # open 1 LV Size 7.00 GiB Current LE 1792 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:2
3. 更新文件系统
[vic@localhost ~]$ sudo resize2fs /dev/linux-vli/sharelv resize2fs 1.42.9 (28-Dec-2013) Filesystem at /dev/linux-vli/sharelv is mounted on /sharelv; on-line resizing required old_desc_blocks = 1, new_desc_blocks = 1 The filesystem on /dev/linux-vli/sharelv is now 1835008 blocks long. [vic@localhost ~]$ df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 6.2G 1.4G 4.9G 22% / devtmpfs 484M 0 484M 0% /dev tmpfs 496M 0 496M 0% /dev/shm tmpfs 496M 6.9M 490M 2% /run tmpfs 496M 0 496M 0% /sys/fs/cgroup /dev/sda1 1014M 132M 883M 14% /boot tmpfs 100M 0 100M 0% /run/user/0 tmpfs 100M 0 100M 0% /run/user/1000 /dev/mapper/linux--vli-sharelv 6.8G 18M 6.5G 1% /sharelv
五. LVM扩大卷组
1. 添加新的硬盘并格式化为PV
[vic@localhost ~]$ sudo pvcreate /dev/sdd Physical volume "/dev/sdd" successfully created. [vic@localhost ~]$ sudo pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <7.00g 0 /dev/sdb linux-vli lvm2 a-- <8.00g 1020.00m /dev/sdc linux-vli lvm2 a-- <8.00g <8.00g /dev/sdd lvm2 --- 8.00g 8.00g [vic@localhost ~]$
2. 将新的PV添加到指定卷组中
[vic@localhost ~]$ sudo vgextend linux-vli /dev/sdd Volume group "linux-vli" successfully extended [vic@localhost ~]$ sudo vgs VG #PV #LV #SN Attr VSize VFree centos 1 2 0 wz--n- <7.00g 0 linux-vli 3 1 0 wz--n- <23.99g <16.99g
六. LVM缩小逻辑卷
1. 卸载已经挂载的逻辑卷
[vic@localhost ~]$ sudo umount /sharelv/
2. 缩小文件系统
[vic@localhost ~]$ sudo e2fsck -f /dev/linux-vli/sharelv 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/linux-vli/sharelv: 12/458752 files (0.0% non-contiguous), 66176/1835008 blocks [vic@localhost ~]$ sudo resize2fs /dev/linux-vli/sharelv 3G resize2fs 1.42.9 (28-Dec-2013) Resizing the filesystem on /dev/linux-vli/sharelv to 786432 (4k) blocks. The filesystem on /dev/linux-vli/sharelv is now 786432 blocks long.
3. 缩小LV
[vic@localhost ~]$ sudo lvreduce -L -3G /dev/linux-vli/sharelv WARNING: Reducing active logical volume to 4.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.) Do you really want to reduce linux-vli/sharelv? [y/n]: y Size of logical volume linux-vli/sharelv changed from 7.00 GiB (1792 extents) to 4.00 GiB (1024 extents). Logical volume linux-vli/sharelv successfully resized. [vic@localhost ~]$ sudo lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert root centos -wi-ao---- <6.20g swap centos -wi-ao---- 820.00m sharelv linux-vli -wi-a----- 4.00g [vic@localhost ~]$ sudo mount /dev/linux-vli/sharelv /sharelv/ [vic@localhost ~]$ cat /sharelv/linuxlv i am linuxlv [vic@localhost ~]$ df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 6.2G 1.4G 4.9G 22% / devtmpfs 484M 0 484M 0% /dev tmpfs 496M 0 496M 0% /dev/shm tmpfs 496M 6.9M 490M 2% /run tmpfs 496M 0 496M 0% /sys/fs/cgroup /dev/sda1 1014M 132M 883M 14% /boot tmpfs 100M 0 100M 0% /run/user/0 tmpfs 100M 0 100M 0% /run/user/1000 /dev/mapper/linux--vli-sharelv 2.9G 13M 2.7G 1% /sharelv
七. 缩小卷组
1. 将PV从卷组中移除
[vic@localhost ~]$ sudo vgreduce linux-vli /dev/sdd Removed "/dev/sdd" from volume group "linux-vli" [vic@localhost ~]$ sudo vgdisplay --- Volume group --- VG Name linux-vli System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 6 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 2 Act PV 2 VG Size 15.99 GiB PE Size 4.00 MiB Total PE 4094 Alloc PE / Size 1024 / 4.00 GiB Free PE / Size 3070 / 11.99 GiB VG UUID 0sJQDx-2Ijp-K0in-jdTs-1fvG-FW2n-n2dXND