1、首先看下当前的文件系统

df -Tm
root@ubuntu:~# df -Tm
Filesystem     Type     1M-blocks  Used Available Use% Mounted on
udev           devtmpfs      1441     0      1441   0% /dev
tmpfs          tmpfs          295     2       293   1% /run
/dev/sda5      ext4         19524  9262      9248  51% /
tmpfs          tmpfs         1474     0      1474   0% /dev/shm

 
2、标红色的是我的根文件系统，可以看到这个文件系统已经使用了51%，共有19G的容量。 

从操作系统的角度看完了之后，从物理层面看下硬盘分区情况，使用fdisk -l 查看

fdisk -l

Disk /dev/sda: 20 GiB, 21474836480 bytes, 41943040 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: dos
Disk identifier: 0x89f0bd9b

Device     Boot   Start      End  Sectors  Size Id Type
/dev/sda1  *       2048  1050623  1048576  512M  b W95 FAT32
/dev/sda2       1052670 41940991 40888322 19.5G  5 Extended
/dev/sda5       1052672 41940991 40888320 19.5G 83 Linux

3、从这里可以看出来，硬盘就一个，然后硬盘分区使用扩展卷的分区，分区名是/dev/sda5

因为我的这台虚拟机没有安装lvm，这里选择安装lvm

root@ubuntu:~# apt install lvm2
Reading package lists... Done
Building dependency tree       
Reading state information... Done

在虚拟机关机的状态时候扩本地磁盘的容量

 扩完磁盘之后，再fdisk 看下磁盘的容量

lion@ubuntu:~$ sudo fdisk -l

Disk /dev/sda: 30 GiB, 32212254720 bytes, 62914560 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: dos
Disk identifier: 0x89f0bd9b

Device     Boot   Start      End  Sectors  Size Id Type
/dev/sda1  *       2048  1050623  1048576  512M  b W95 FAT32
/dev/sda2       1052670 41940991 40888322 19.5G  5 Extended
/dev/sda5       1052672 41940991 40888320 19.5G 83 Linux

4、能看到整个sda磁盘30G，已经分配的/dev/sda5 还是之后19.5G的容量，这时候我们就可以把10G的磁盘空间分配给/home的空间，这里我们用逻辑卷的模式来进行

首先格式化磁盘空间

fdisk /dev/sda

root@ubuntu:~# fdisk /dev/sda

Welcome to fdisk (util-linux 2.34).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): m
Help:

  DOS (MBR)
   a   toggle a bootable flag
   b   edit nested BSD disklabel
   c   toggle the dos compatibility flag

  Generic
   d   delete a partition
   F   list free unpartitioned space
   l   list known partition types
   n   add a new partition
   p   print the partition table
   t   change a partition type
   v   verify the partition table
   i   print information about a partition

  Misc
   m   print this menu
   u   change display/entry units
   x   extra functionality (experts only)

  Script
   I   load disk layout from sfdisk script file
   O   dump disk layout to sfdisk script file

  Save & Exit
   w   write table to disk and exit
   q   quit without saving changes

  Create a new label
   g   create a new empty GPT partition table
   G   create a new empty SGI (IRIX) partition table
   o   create a new empty DOS partition table
   s   create a new empty Sun partition table

 

5、输入m 打开帮助，读这里的选项，我们就能够找到增加一个分区的，输入n，这里我们增加一个主分区，所有后面输入p，然后默认的从扇区编号41940992-62914559意思是将磁盘多余的扇区都分配出来

Command (m for help): n
Partition type
   p   primary (1 primary, 1 extended, 2 free)
   l   logical (numbered from 5)
Select (default p): p
Partition number (3,4, default 3): 
First sector (41940992-62914559, default 41940992): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (41940992-62914559, default 62914559): 

Created a new partition 3 of type 'Linux' and of size 10 GiB.

上面已经显示了有10G的空间，然后输入w，保存这个磁盘分区表

Command (m for help): n
Partition type
   p   primary (1 primary, 1 extended, 2 free)
   l   logical (numbered from 5)
Select (default p): p
Partition number (3,4, default 3): 
First sector (41940992-62914559, default 41940992): 
Last sector, +/-sectors or +/-size{K,M,G,T,P} (41940992-62914559, default 62914559): 

Created a new partition 3 of type 'Linux' and of size 10 GiB.

Command (m for help): w
The partition table has been altered.
Syncing disks.

6、再执行fdisk 我们就能看到我们刚才创建的sda3这个分区了

现在我们用这个sda3创建pv，使用pvcreate + 分区

 root@ubuntu:~# pvcreate /dev/sda3
  Physical volume "/dev/sda3" successfully created.
root@ubuntu:~# 
root@ubuntu:~# 

然后创建vg

root@ubuntu:~# vgcreate vghome /dev/sda3
  Volume group "vghome" successfully created

然后创建lv

root@ubuntu:~# lvcreate -n lvhome -l 100%FREE vghome
  Logical volume "lvhome" created.

这个就表示了用100%剩余的刚刚创建的vghome这个卷组创建逻辑卷

此时查看逻辑卷就能够查看到了

root@ubuntu:~# lvdisplay
  --- Logical volume ---
  LV Path                /dev/vghome/lvhome
  LV Name                lvhome
  VG Name                vghome
  LV UUID                hCav9V-HfJL-b1yM-FBKK-7cjJ-167J-uRiKTA
  LV Write Access        read/write
  LV Creation host, time ubuntu, 2022-06-26 05:22:37 -0700
  LV Status              available
  # open                 0
  LV Size                10.00 GiB
  Current LE             2560
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

7、完成了之后给逻辑卷创建文件系统

root@ubuntu:~# mkfs.ext4 /dev/vghome/lvhome
mke2fs 1.45.5 (07-Jan-2020)
Creating filesystem with 2621440 4k blocks and 655360 inodes
Filesystem UUID: 19147237-cf28-40b8-84e2-3e9a96bcb5ce
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done 

8、这个时候就可以挂载了

mount /dev/vghome/lvhome /home

9、下面这一步不要忘了，否则每次重启的时候都要重复挂载

vim /etc/fstab

加入这一行即可

/dev/vghome/lvhome  /home       ext4    errors=remount-ro 0 0 

重新挂载  umount   /home
删除逻辑卷  lvremove   vgremove  pvremove