在我们安装ubuntu时，如果选择的是自动分区，就会按照逻辑卷的形式来分区，并且只分配100G其余的并不会被分配，这对我们大多数情况来说都是不合理的，所以，如何扩充呢
下面以一个小的案例来说明如何扩充
问题
磁盘空间已满
Usage of /: 99.8% of 9.75GBdf、fdisk查看磁盘占用情况
df -hroot@summergao:~# df -h
Filesystem Size Used Avail Use% Mounted on
udev 16G 0 16G 0% /dev
tmpfs 3.2G 2.2M 3.2G 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 98G 97G 0G 100% /
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/loop0 64M 64M 0 100% /snap/core20/1828
/dev/loop2 50M 50M 0 100% /snap/snapd/18357
/dev/loop1 92M 92M 0 100% /snap/lxd/24061
/dev/sda2 2.0G 112M 1.7G 7% /boot
/dev/sda1 1.1G 6.1M 1.1G 1% /boot/efi
tmpfs 3.2G 0 3.2G 0% /run/user/0
root@summergao:~#
fdisk -lroot@summergao:~# fdisk -l
Disk /dev/loop0: 63.29 MiB, 66359296 bytes, 129608 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 /dev/loop1: 91.85 MiB, 96292864 bytes, 188072 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 /dev/loop2: 49.86 MiB, 52260864 bytes, 102072 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 /dev/sda: 9.1 TiB, 10000294477824 bytes, 19531825152 sectors
Disk model: PERC H330 Mini
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: FCB82ED5-B67D-4AF4-914E-1045C910D2E7
Device Start End Sectors Size Type
/dev/sda1 2048 2203647 2201600 1.1G EFI System
/dev/sda2 2203648 6397951 4194304 2G Linux filesystem
/dev/sda3 6397952 19531823103 19525425152 9.1T Linux filesystem
Disk /dev/mapper/ubuntu--vg-ubuntu--lv: 100 GiB, 107374182400 bytes, 209715200 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
root@summergao:~#查看磁盘挂载情况
lsblkroot@summergao:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 63.3M 1 loop /snap/core20/1828
loop1 7:1 0 91.9M 1 loop /snap/lxd/24061
loop2 7:2 0 49.9M 1 loop /snap/snapd/18357
sda 8:0 0 9.1T 0 disk
├─sda1 8:1 0 1.1G 0 part /boot/efi
├─sda2 8:2 0 2G 0 part /boot
└─sda3 8:3 0 9.1T 0 part
└─ubuntu--vg-ubuntu--lv 253:0 0 100G 0 lvm /
sr0 11:0 1 1024M 0 rom
root@summergao:~#
可以看到sda3有9.1T，但是只分配了100G。
命令vgdisplay可以查看lvm卷组的信息
root@summergao:~# vgdisplay
--- Volume group ---
VG Name ubuntu-vg
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 2
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 9.09 TiB
PE Size 4.00 MiB
Total PE 2383474
Alloc PE / Size 25600 / 100.00 GiB
Free PE / Size 2357874 / 8.99 TiB
VG UUID tsCO25-L5Rx-2qGn-2l1e-6vl0-fjJl-HaweHl
root@summergao:~#如果看到 Free PE / Size > 0，表示还有扩容空间。
Free PE / Size 2357874 / 8.99 TiB 这是还可以扩容的大小 。
解决办法
使用命令进行磁盘扩容
扩容指令示例如下：
#lvextend -L +10G /dev/mapper/ubuntu--vg-ubuntu--lv //增加10G
#lvreduce -L -10G /dev/mapper/ubuntu--vg-ubuntu--lv //减小10G
#lvresize -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv //按百分比扩这里选择将所有空闲磁盘全部用来扩容
lvresize -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lvroot@summergao:~# lvresize -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv
Size of logical volume ubuntu-vg/ubuntu-lv changed from 100.00 GiB (25600 extents) to 9.09 TiB (2383474 extents).
Logical volume ubuntu-vg/ubuntu-lv successfully resized.
root@summergao:~# 执行resize2fs使扩容生效 （注意：不执行这个命令以上修改是不会生效的！）
resize2fs /dev/mapper/ubuntu--vg-ubuntu--lvroot@summergao:~# resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv
resize2fs 1.45.5 (07-Jan-2020)
Filesystem at /dev/mapper/ubuntu--vg-ubuntu--lv is mounted on /; on-line resizing required
old_desc_blocks = 13, new_desc_blocks = 1164
The filesystem on /dev/mapper/ubuntu--vg-ubuntu--lv is now 2440677376 (4k) blocks long.
root@summergao:~#
查看扩容结果
再次查看LVM卷组的信息，以及分区空间大小
vgdisplayroot@summergao:~# 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 9.09 TiB
PE Size 4.00 MiB
Total PE 2383474
Alloc PE / Size 2383474 / 9.09 TiB
Free PE / Size 0 / 0
VG UUID tsCO25-L5Rx-2qGn-2l1e-6vl0-fjJl-HaweHl可以看到此时Free PE / Size 已经为0了
df -h root@summergao:~# df -h
Filesystem Size Used Avail Use% Mounted on
udev 16G 0 16G 0% /dev
tmpfs 3.2G 2.2M 3.2G 1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv 9.0T 11G 8.6T 1% /
tmpfs 16G 0 16G 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/loop0 64M 64M 0 100% /snap/core20/1828
/dev/loop2 50M 50M 0 100% /snap/snapd/18357
/dev/loop1 92M 92M 0 100% /snap/lxd/24061
/dev/sda2 2.0G 112M 1.7G 7% /boot
/dev/sda1 1.1G 6.1M 1.1G 1% /boot/efi
tmpfs 3.2G 0 3.2G 0% /run/user/0
root@summergao:~# 查看当前磁盘大小已经扩容到9.0T了
参考
ubuntu的ubuntu--vg-ubuntu--lv磁盘扩容 - 厚礼蝎 - 博客园
ubuntu server版 虚拟机根目录磁盘扩容_ubuntu--vg-ubuntu--lv只有100g-CSDN博客