物理卷 Physical Volume(PV)： 可以在上面建立卷组的媒介，可以使硬盘分区，也可以是硬盘本身或者回环（loopback file）。物理卷包括一个特殊的header，其余部分被切割为一块物理区域（Physical extent）
卷组 Volume group(VG)： 将一组物理卷收集为一个管理单元
逻辑卷 Logucal voiume(LV)： 虚拟分区，有物理区域（Physical extent）组成
物理区域 Physical extent(PE)： 硬盘可供指派给逻辑卷的最小单位（通常为4MB）
背景：虚拟机磁盘10G，新挂载了一块5G的磁盘
一、查看系统磁盘情况
1、查看挂载点
[root@localhost ~]# df -Th
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 475M 0 475M 0% /dev
tmpfs 487M 0 487M 0% /dev/shm
tmpfs 487M 7.6M 479M 2% /run
tmpfs 487M 0 487M 0% /sys/fs/cgroup
/dev/mapper/centos-root 8.0G 1.4G 6.7G 17% /
/dev/sda1 1014M 137M 878M 14% /boot
tmpfs 98M 0 98M 0% /run/user/0
[root@localhost ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 10G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 9G 0 part
├─centos-root 253:0 0 8G 0 lvm /
└─centos-swap 253:1 0 1G 0 lvm [SWAP]
sdb 8:16 0 5G 0 disk
sr0 11:0 1 1024M 0 rom
2、显示当前Logucal voiume
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID wUFT8g-Ek1L-y2Na-okKj-W6FR-1hsG-fGsLca
LV Write Access read/write
LV Creation host, time localhost, 2026-03-18T23:26:14+00:00 -0400
LV Status available
# open 2
LV Size 1.00 GiB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID WYZHEW-4tFT-nIFv-lNqs-jeL2-RrTE-tecnXr
LV Write Access read/write
LV Creation host, time localhost, 2026-03-18T23:26:14+00:00 -0400
LV Status available
# open 1
LV Size <8.00 GiB
Current LE 2047
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
3、显示当前Volume group
[root@localhost ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size <9.00 GiB
PE Size 4.00 MiB
Total PE 2303
Alloc PE / Size 2303 / <9.00 GiB
Free PE / Size 0 / 0
VG UUID QGhqYf-HT0c-f2Sl-J7pj-6sq5-eALu-2d3xDx
4、显示当前Physical Volume
[root@localhost ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size <9.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2303
Free PE 0
Allocated PE 2303
PV UUID H6nAis-TqW8-3Zy1-MJ0a-0i5U-6hHK-FodvW6
二、开始LVM扩容
1、查看新磁盘
[root@localhost ~]# fdisk -l
Disk /dev/sda: 10.7 GB, 10737418240 bytes, 20971520 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: 0x000d4ea1
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 20971519 9436160 8e Linux LVM
Disk /dev/sdb: 5368 MB, 5368709120 bytes, 10485760 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/mapper/centos-root: 8585 MB, 8585740288 bytes, 16769024 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/mapper/centos-swap: 1073 MB, 1073741824 bytes, 2097152 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
2、新磁盘创建新分区
[root@localhost ~]# fdisk /dev/sdb
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 0x3a867d96.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p):
Using default response p
Partition number (1-4, default 1):
First sector (2048-10485759, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-10485759, default 10485759):
Using default value 10485759
Partition 1 of type Linux and of size 5 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
3、开始格式化新磁盘
[root@localhost ~]# fdisk -l
Disk /dev/sda: 10.7 GB, 10737418240 bytes, 20971520 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: 0x000d4ea1
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 20971519 9436160 8e Linux LVM
Disk /dev/sdb: 5368 MB, 5368709120 bytes, 10485760 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: 0x3a867d96
Device Boot Start End Blocks Id System
/dev/sdb1 2048 10485759 5241856 83 Linux
Disk /dev/mapper/centos-root: 8585 MB, 8585740288 bytes, 16769024 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/mapper/centos-swap: 1073 MB, 1073741824 bytes, 2097152 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
# 格式化新磁盘分区为xfs格式
[root@localhost ~]# mkfs -t xfs /dev/sdb1
meta-data=/dev/sdb1 isize=512 agcount=4, agsize=1966016 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=7864064, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=3839, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
# 格式化新磁盘分区为ext4格式
[root@localhost ~]# mkfs -t ext4 /dev/sdb1
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
327680 inodes, 1310464 blocks
65523 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 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
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
4、创建PV
[root@localhost ~]# pvcreate /dev/sdb1
WARNING: ext4 signature detected on /dev/sdb1 at offset 1080. Wipe it? [y/n]: y
Wiping ext4 signature on /dev/sdb1.
Physical volume "/dev/sdb1" successfully created.
5、查看卷组
[root@localhost ~]# pvscan
PV /dev/sda2 VG centos lvm2 [<9.00 GiB / 0 free]
PV /dev/sdb1 lvm2 [<5.00 GiB]
Total: 2 [<14.00 GiB] / in use: 1 [<9.00 GiB] / in no VG: 1 [<5.00 GiB]
6、扩容vg
[root@localhost ~]# vgextend centos /dev/sdb1
Volume group "centos" successfully extended
[root@localhost ~]# pvscan
PV /dev/sda2 VG centos lvm2 [<9.00 GiB / 0 free]
PV /dev/sdb1 VG centos lvm2 [<5.00 GiB / <5.00 GiB free]
Total: 2 [13.99 GiB] / in use: 2 [13.99 GiB] / in no VG: 0 [0 ]
7、查看VG和LV
[root@localhost ~]# vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 13.99 GiB
PE Size 4.00 MiB
Total PE 3582
Alloc PE / Size 2303 / <9.00 GiB
Free PE / Size 1279 / <5.00 GiB
VG UUID QGhqYf-HT0c-f2Sl-J7pj-6sq5-eALu-2d3xDx
[root@localhost ~]# lvdisplay
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID wUFT8g-Ek1L-y2Na-okKj-W6FR-1hsG-fGsLca
LV Write Access read/write
LV Creation host, time localhost, 2026-03-18T23:26:14+00:00 -0400
LV Status available
# open 2
LV Size 1.00 GiB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID WYZHEW-4tFT-nIFv-lNqs-jeL2-RrTE-tecnXr
LV Write Access read/write
LV Creation host, time localhost, 2026-03-18T23:26:14+00:00 -0400
LV Status available
# open 1
LV Size <8.00 GiB
Current LE 2047
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
8、LV逻辑卷扩容
# 按固定大小扩容
[root@localhost ~]# lvextend -L +5G /dev/centos/root
# 按百分比扩容
[root@localhost ~]# lvextend -l +100%FREE /dev/centos/root
Size of logical volume centos/root changed from <8.00 GiB (2047 extents) to 12.99 GiB (3326 extents).
Logical volume centos/root successfully resized.
9、刷新LV
# 使用 resize2fs 进行刷新LV路径 报错
[root@localhost ~]# resize2fs /dev/centos/root
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open /dev/centos/root
Couldn't find valid filesystem superblock.
# 发现报错 需要使用mount |grep root进行查看LV路径的文件格式是什么 发现是xfs文件系统
[root@localhost ~]# mount |grep root
/dev/mapper/centos-root on / type xfs (rw,relatime,seclabel,attr2,inode64,noquota)
# xfs文件系统使用如下命令进行刷新
[root@localhost ~]# xfs_growfs /dev/centos/root
meta-data=/dev/mapper/centos-root isize=512 agcount=4, agsize=524032 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=2096128, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 2096128 to 3405824
10、查看大小发现已经有13G的空间了
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 475M 0 475M 0% /dev
tmpfs 487M 0 487M 0% /dev/shm
tmpfs 487M 7.7M 479M 2% /run
tmpfs 487M 0 487M 0% /sys/fs/cgroup
/dev/mapper/centos-root 13G 1.4G 12G 11% /
/dev/sda1 1014M 137M 878M 14% /boot
tmpfs 98M 0 98M 0% /run/user/0