在使用虚拟机过程中，可能会遇到需要扩展磁盘容量的情况，而Ubuntu作为一种常见的操作系统，我们将介绍如何动态调整分区以适应磁盘大小的变更。
pv、lv、vg 介绍
PV（Phsical Volume，物理卷），PV是VG的组成部分，由分区构成，多块盘的时候，可以把一块盘格式化成一个主分区，然后用这个分区做成一个PV，只有一块盘的时候，可以这块盘的某一个分区做成一个PV，实际上一个PV就一个分区。
VG（Volume Group， 卷组），有若干个PV组成，作用就是将PV组成到以前，然后再重新划分空间。
LV（Logical Volume，逻辑卷），LV就是从VG中划分出来的卷，LV的使用要比PV灵活的多，可以在空间不够的情况下，增加空间。
可以说成是PV就是硬盘,而VG就是管理硬盘的操作系统,而LV就是操作系统分出来的各个分区.
PV->VG->LV-> 文件系统使用(挂载到某个目录)
硬盘或分区做成pv，然后将pv或多个pv建立vg，vg上建立lv,其模型如下
命令集合
PV
pvcreate :根据物理盘,创建pv
pvscan :查询目前系统里的pv
pvdisplay:显示pv的状态
pvremove:将pv属性移除
VG
vgcreate:创建vg
vgscan:查找当前系统里面的vg
vgdisplay:显示当前系统vg的状态
vgextend:给vg添加额外的pv
vgreduce:在vg内删除pv
vgchange:设置vg是否是启动状态(active)
vgremove:删除一个vg
LV
lvcreate:创建lv
lvscan:查询当前系统的lv
lvdisplay:显示lv的属性
lvextend:给lv添加容量
lvredurce:给lv减少容量
lvremove:删除一个lv
lvresize:对lv大小的容量进行调整
实战案例
查看文件系统的磁盘空间使用情况
df -hl
Filesystem Size Used Avail Use% Mounted on
tmpfs 791M 2.2M 789M 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 38G 26G 11G 72% /
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/sda2 2.0G 253M 1.6G 14% /boot
tmpfs 791M 4.0K 791M 1% /run/user/1000
可以看到 / 由 /dev/mapper/ubuntu–vg-ubuntu–lv 挂载
创建分区 sda4，将设置为 lvm 类型：
sudo fdisk /dev/sda
xiuji@xiuji:~$ sudo fdisk /dev/sda
Welcome to fdisk (util-linux 2.37.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
GPT PMBR size mismatch (83886079 != 209715199) will be corrected by write.
This disk is currently in use - repartitioning is probably a bad idea.
It's recommended to umount all file systems, and swapoff all swap
partitions on this disk.
Command (m for help): p
Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: D80D8A91-AB36-4BB8-A669-783F46148D68
Device Start End Sectors Size Type
/dev/sda1 2048 4095 2048 1M BIOS boot
/dev/sda2 4096 4198399 4194304 2G Linux filesystem
/dev/sda3 4198400 83884031 79685632 38G Linux filesystem
Command (m for help): n
Partition number (4-128, default 4): 4
First sector (83884032-209715166, default 83884032): 83884032
Last sector, +/-sectors or +/-size{K,M,G,T,P} (83884032-209715166, default 209715166): 104857583
Created a new partition 4 of type 'Linux filesystem' and of size 10 GiB.
Command (m for help): p
Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: D80D8A91-AB36-4BB8-A669-783F46148D68
Device Start End Sectors Size Type
/dev/sda1 2048 4095 2048 1M BIOS boot
/dev/sda2 4096 4198399 4194304 2G Linux filesystem
/dev/sda3 4198400 83884031 79685632 38G Linux filesystem
/dev/sda4 83884032 104857583 20973552 10G Linux filesystem
Command (m for help): t
Partition number (1-4, default 4): 4
Partition type or alias (type L to list all): lvm
Changed type of partition 'Linux filesystem' to 'Linux LVM'.
Command (m for help): p
Disk /dev/sda: 100 GiB, 107374182400 bytes, 209715200 sectors
Disk model: VMware Virtual S
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: D80D8A91-AB36-4BB8-A669-783F46148D68
Device Start End Sectors Size Type
/dev/sda1 2048 4095 2048 1M BIOS boot
/dev/sda2 4096 4198399 4194304 2G Linux filesystem
/dev/sda3 4198400 83884031 79685632 38G Linux filesystem
/dev/sda4 83884032 104857583 20973552 10G Linux LVM
Command (m for help): w
The partition table has been altered.
Syncing disks.
sda4 创建成功，查看所有可用空间：
sudo lsblk
xiuji@xiuji:~$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 63.4M 1 loop /snap/core20/1950
loop1 7:1 0 53.3M 1 loop /snap/snapd/19457
loop2 7:2 0 53.3M 1 loop /snap/snapd/19361
loop3 7:3 0 63.5M 1 loop /snap/core20/1891
loop4 7:4 0 111.9M 1 loop /snap/lxd/24322
sda 8:0 0 100G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 2G 0 part /boot
├─sda3 8:3 0 38G 0 part
│ └─ubuntu--vg-ubuntu--lv 253:0 0 38G 0 lvm /
└─sda4 8:4 0 10G 0 part
sr0 11:0 1 1.8G 0 rom
将 sda4创建成 PV(Physical Volume)：
sudo pvcreate /dev/sda4
xiuji@xiuji:~$ sudo pvcreate /dev/sda4
Physical volume "/dev/sda4" successfully created.
sudo pvdisplay
xiuji@xiuji:~$ sudo pvdisplay
--- Physical volume ---
PV Name /dev/sda3
VG Name ubuntu-vg
PV Size <38.00 GiB / not usable 0
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 9727
Free PE 0
Allocated PE 9727
PV UUID qtpZ00-5KSl-HJr3-GCcf-Ki6B-eQP8-pcO6oH
"/dev/sda4" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sda4
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID eKegVq-phGh-jZ51-p08D-go8S-fFvt-8DLU62
查看当前 VG
sudo vgdisplay
xiuji@xiuji:~$ sudo vgdisplay
--- Volume group ---
VG Name ubuntu-vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 1
Act PV 1
VG Size <38.00 GiB
PE Size 4.00 MiB
Total PE 9727
Alloc PE / Size 9727 / <38.00 GiB
Free PE / Size 0 / 0
VG UUID vy0kkj-d2tU-Izec-RFY0-1Nmx-cReb-3Kx2S7
将 PV 添加到 VG
sudo vgextend ubuntu-vg /dev/sda4
xiuji@xiuji:~$ sudo vgextend ubuntu-vg /dev/sda4
Volume group "ubuntu-vg" successfully extende
sudo vgdisplay
xiuji@xiuji:~$ sudo vgdisplay
--- Volume group ---
VG Name ubuntu-vg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
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 47.99 GiB
PE Size 4.00 MiB
Total PE 12286
Alloc PE / Size 9727 / <38.00 GiB
Free PE / Size 2559 / <10.00 GiB
VG UUID vy0kkj-d2tU-Izec-RFY0-1Nmx-cReb-3Kx2S7
块设备（block devices）的信息
sudo lsblk
xiuji@xiuji:~$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 63.4M 1 loop /snap/core20/1950
loop1 7:1 0 53.3M 1 loop /snap/snapd/19457
loop2 7:2 0 53.3M 1 loop /snap/snapd/19361
loop3 7:3 0 63.5M 1 loop /snap/core20/1891
loop4 7:4 0 111.9M 1 loop /snap/lxd/24322
sda 8:0 0 100G 0 disk
├─sda1 8:1 0 1M 0 part
├─sda2 8:2 0 2G 0 part /boot
├─sda3 8:3 0 38G 0 part
│ └─ubuntu--vg-ubuntu--lv 253:0 0 38G 0 lvm /
└─sda4 8:4 0 10G 0 part
sr0 11:0 1 1.8G 0 rom
调整 LV 占用 VG 的全部空间
sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
xiuji@xiuji:~$ sudo lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
Size of logical volume ubuntu-vg/ubuntu-lv changed from <38.00 GiB (9727 extents) to 47.99 GiB (12286 extents).
Logical volume ubuntu-vg/ubuntu-lv successfully resized.
sudo resize2fs /dev/ubuntu-vg/ubuntu-lv
xiuji@xiuji:~$ sudo resize2fs /dev/ubuntu-vg/ubuntu-lv
resize2fs 1.46.5 (30-Dec-2021)
Filesystem at /dev/ubuntu-vg/ubuntu-lv is mounted on /; on-line resizing required
old_desc_blocks = 5, new_desc_blocks = 6
The filesystem on /dev/ubuntu-vg/ubuntu-lv is now 12580864 (4k) blocks long.
查看文件系统的磁盘空间使用情况
df -hl
xiuji@xiuji:~$ df -hl
Filesystem Size Used Avail Use% Mounted on
tmpfs 791M 2.2M 789M 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 48G 26G 20G 57% /
tmpfs 3.9G 0 3.9G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/sda2 2.0G 253M 1.6G 14% /boot
tmpfs 791M 4.0K 791M 1% /run/user/1000
可以看到我们/dev/mapper/ubuntu–vg-ubuntu–lv调整了10G的大小已经生效了