Ubuntu扩展根目录空间（扩展原有分区）

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0.概念说明

一切开始的开始 先说明一些概念

物理卷（Physical Volume）即PV： 物理卷就是指硬盘分区或从逻辑上与磁盘分区具有同样功能的设备(如RAID)，是LVM的基本存储逻辑块，但和基本的物理存储介质（如分区、磁盘等）比较，却包含有与LVM相关的管理参数。
卷组（Volume Group）即VG： LVM卷组类似于非LVM系统中的物理硬盘，其由物理卷组成。可以在卷组上创建一个或多个“LVM分区”（逻辑卷），LVM卷组由一个或多个物理卷组成。
逻辑卷（Logical Volume）即LV： LVM的逻辑卷类似于非LVM系统中的硬盘分区，在逻辑卷之上可以建立文件系统(比如/home或者/usr等)。

总之 LV建立在VG之上，VG建立在PV之上，是PV的集合，PV即物理卷。

本文的总体思路为： 扩容PV-> 扩容LV -> 扩容根目录空间

1.VM添加空间

使用vmware增加空间 ↓
在这里插入图片描述

2.使用fdisk扩展原有分区

此处参考了Linux下使用fdisk扩展分区容量，原文关键部分摘录如下

对/dev/sda4进行扩容

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[root@linuxprobe ~]: fdisk /dev/sda #对/dev/sda进行操作

WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
         switch off the mode (command 'c') and change display units to
         sectors (command 'u').

Command (m for help): p        #查看分区表信息

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0005210c

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          26      204800   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              26        1301    10240000   83  Linux
/dev/sda3            1301        1497     1572864   82  Linux swap / Solaris
/dev/sda4            1497        2611     8952832   83  Linux

Command (m for help): d           #删除分区
Partition number (1-4): 4         #删除需要扩容的分区（这里为sda4）

Command (m for help): p       #再次查看分区信息，/dev/sda4已被删除

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0005210c

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          26      204800   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              26        1301    10240000   83  Linux
/dev/sda3            1301        1497     1572864   82  Linux swap / Solaris

Command (m for help): n      #创建新的分区
Command action
   e   extended
   p   primary partition (1-4)
p             #创建为主分区
Selected partition 4
First cylinder (1497-3916, default 1497):          #经对比，正好和上一个磁盘柱一致，默认即可
Using default value 1497
Last cylinder, +cylinders or +size{K,M,G} (1497-3916, default 3916): 
Using default value 3916              #直接默认就可以

Command (m for help): p               #查看分区表信息

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0005210c

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          26      204800   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              26        1301    10240000   83  Linux
/dev/sda3            1301        1497     1572864   82  Linux swap / Solaris
/dev/sda4            1497        3916    19436582   83  Linux

Command (m for help): wp       #保存并退出，如果创建有误，直接退出不要保存即可
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
Syncing disks.

3.刷新PV空间

对分区扩容完成后，会发现空间依旧没有增加，此时需要先刷新pv大小，使用pvresize:

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[root@syra-ti_ubuntu~]: pvdisplay #先列出pv
  --- Physical volume ---
  PV Name               /dev/sda4
  VG Name               ubuntu-vg
  PV Size               <19.00 GiB / not usable 16.50 KiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              9983
  Free PE               0
  Allocated PE          9983
  PV UUID               2CF0fb-auL8-N1Xk-Lpo1-pdzo-MLN5-R0QAIX
  
[root@syra-ti_ubuntu~]: pvresize /dev/sda4 #调用pvresize进行刷新
  Physical volume "/dev/sda3" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized

[root@syra-ti_ubuntu~]: pvdisplay #再次查看pv大小 发现pv大小已经正常
  --- Physical volume ---
  PV Name               /dev/sda4
  VG Name               ubuntu-vg
  PV Size               <39.00 GiB / not usable 16.50 KiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              9983
  Free PE               0
  Allocated PE          9983
  PV UUID               2CF0fb-auL8-N1Xk-Lpo1-pdzo-MLN5-R0QAIX

4.为LV增加空间

对pv扩容完成后，会发现lv的空间依旧没有增加，此时需要扩展lv大小，使用lvextend:

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[root@syra-ti_ubuntu~]: lvdisplay #列出lv信息 发现lv空间没有增加
  --- Logical volume ---
  LV Path                /dev/ubuntu-vg/ubuntu-lv
  LV Name                ubuntu-lv
  VG Name                ubuntu-vg
  LV UUID                3THGqb-Me9D-KFEK-QxT5-dP8Y-hUqa-knbAa3
  LV Write Access        read/write
  LV Creation host, time ubuntu-server, 2021-10-12 06:49:31 +0000
  LV Status              available
  # open                 1
  LV Size                <19.00 GiB
  Current LE             9983
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
[root@syra-ti_ubuntu~]: lvextend -L +20G /dev/ubuntu-vg/ubuntu-lv /dev/sda4 #调用lvextend进行扩容
[root@syra-ti_ubuntu~]: lvdisplay #再次列出lv信息 发现lv空间已经增加
  --- Logical volume ---
  LV Path                /dev/ubuntu-vg/ubuntu-lv
  LV Name                ubuntu-lv
  VG Name                ubuntu-vg
  LV UUID                3THGqb-Me9D-KFEK-QxT5-dP8Y-hUqa-knbAa3
  LV Write Access        read/write
  LV Creation host, time ubuntu-server, 2021-10-12 06:49:31 +0000
  LV Status              available
  # open                 1
  LV Size                <39.00 GiB
  Current LE             9983
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

5.扩展根目录空间

对lv扩容完成后，会发现根目录的空间依旧没有增加，此时需要刷新根目录大小，使用resize2fs:

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[root@syra-ti_ubuntu~]: df -h #发现/根目录空间还是没有增加
Filesystem                         Size  Used Avail Use% Mounted on
udev                               1.9G     0  1.9G   0% /dev
tmpfs                              393M  1.8M  391M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   19G   18G   19G  99% /
tmpfs                              2.0G     0  2.0G   0% /dev/shm
tmpfs                              5.0M     0  5.0M   0% /run/lock
tmpfs                              2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/loop0                          56M   56M     0 100% /snap/core18/2128
/dev/loop1                          56M   56M     0 100% /snap/core18/2253
/dev/loop3                          43M   43M     0 100% /snap/snapd/14066
/dev/loop2                         117M  117M     0 100% /snap/docker/1125
/dev/loop4                          33M   33M     0 100% /snap/snapd/13270
/dev/sda2                          976M  150M  759M  17% /boot
tmpfs                              393M     0  393M   0% /run/user/0

[root@syra-ti_ubuntu~]: resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv #使用resize2fs进行刷新
resize2fs 1.44.1 (24-Mar-2018)
Filesystem at /dev/mapper/ubuntu--vg-ubuntu--lv is mounted on /; on-line resizing required
old_desc_blocks = 3, new_desc_blocks = 5
The filesystem on /dev/mapper/ubuntu--vg-ubuntu--lv is now 10222592 (4k) blocks long.

[root@syra-ti_ubuntu~]: df -h #再次查看，发现/根目录空间已经增加
Filesystem                         Size  Used Avail Use% Mounted on
udev                               1.9G     0  1.9G   0% /dev
tmpfs                              393M  1.8M  391M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   39G   18G   19G  49% /
tmpfs                              2.0G     0  2.0G   0% /dev/shm
tmpfs                              5.0M     0  5.0M   0% /run/lock
tmpfs                              2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/loop0                          56M   56M     0 100% /snap/core18/2128
/dev/loop1                          56M   56M     0 100% /snap/core18/2253
/dev/loop3                          43M   43M     0 100% /snap/snapd/14066
/dev/loop2                         117M  117M     0 100% /snap/docker/1125
/dev/loop4                          33M   33M     0 100% /snap/snapd/13270
/dev/sda2                          976M  150M  759M  17% /boot
tmpfs                              393M     0  393M   0% /run/user/0

以上！まいど～