1. 概述

LVM = Logical Volume Manager，直译为 “逻辑卷组管理”，它解决了常规磁盘分区大小无法伸缩的问题

磁盘 -> PV -> VG -> LV

• 每个磁盘分区对应一个物理卷组（PV）
• 多个物理卷组（PV）组成逻辑卷组（VG）
• 逻辑卷组（VG）划分给多个逻辑卷（LV）

image.png

2. 分区扩容

2.1. 磁盘 -> PV

# 查看系统磁盘，有/dev/vda 和  /dev/vdb 共2个物理分区
[root@bd107 ~]# fdisk -l

Disk /dev/vda: 42.9 GB, 42949672960 bytes, 83886080 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: 0x00099229

   Device Boot      Start         End      Blocks   Id  System
/dev/vda1   *        2048     2099199     1048576   83  Linux
/dev/vda2         2099200    83886079    40893440   8e  Linux LVM

Disk /dev/mapper/cl-root: 536.9 GB, 536870912000 bytes, 1048576000 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/cl-swap: 4160 MB, 4160749568 bytes, 8126464 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/vdb: 536.9 GB, 536870912000 bytes, 1048576000 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

# 磁盘转PV
pvcreate /dev/vdb

2.2. PV -> VG

# 查看vg命名空间，名称为cl
[root@bd107 ~]# vgdisplay 
  --- Volume group ---
  VG Name               cl
  System ID             
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  5
  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               538.99 GiB
  PE Size               4.00 MiB
  Total PE              137982
  Alloc PE / Size       128992 / 503.88 GiB
  Free  PE / Size       8990 / 35.12 GiB
  VG UUID               T7Ovhi-Mk5V-Ry9y-s8RV-9ihc-pvgq-am0g0V

# 将2.1步创建的pv加入到cl
vgextend cl /dev/vdb

2.3. VG -> LV

# 查看逻辑卷路径，其中根分区路径为/dev/cl/root
[root@bd107 ~]# lvdisplay 
  --- Logical volume ---
  LV Path                /dev/cl/swap
  LV Name                swap
  VG Name                cl
  LV UUID                QCN8wW-Ic4K-l3SM-LRYF-2t06-K6wM-AQoOlK
  LV Write Access        read/write
  LV Creation host, time 172-31-128-183, 2021-06-07 17:12:59 +0800
  LV Status              available
  # open                 2
  LV Size                3.88 GiB
  Current LE             992
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/cl/root
  LV Name                root
  VG Name                cl
  LV UUID                WFIxvP-BIkN-CIJt-6UQY-kn6D-iqu1-c4n2HL
  LV Write Access        read/write
  LV Creation host, time 172-31-128-183, 2021-06-07 17:12:59 +0800
  LV Status              available
  # open                 1
  LV Size                500.00 GiB
  Current LE             128000
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

# 扩展根分区大小
lvextend -l 100%FREE /dev/cl/root /dev/vdb

2.4. 刷新分区

适用于centos7版本

xfs_growfs /