linux服务器Centos7将home空间分配给根目录（/dev/centos/root）

命令汇总

简单总结下，就是下面几条命令：

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mkdir /backup
mv /home/* /backup/
umount /home
lvremove /dev/centos/home
lvcreate -L 50G -n home cents
mkfs -t xfs /dev/centos/home
mv /backup/* /home/
lvextend -L +xxxG /dev/centos/root
xfs_growfs root
rm -rf /backup

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在安装centos系统的时候，如果在安装时没有分配磁盘空间，选择的是默认分配的，在安装完成后，可以发现大容量磁盘往往分配在了home下面。
在没有大量自定义用户使用的情况下，home的空间基本不用时，可以将空间转移至root下面。

查看目录结构

[root@mrf-server opt]# df -hl
文件系统                 容量  已用  可用 已用% 挂载点
devtmpfs                 7.7G     0  7.7G    0% /dev
tmpfs                    7.7G     0  7.7G    0% /dev/shm
tmpfs                    7.7G   18M  7.7G    1% /run
tmpfs                    7.7G     0  7.7G    0% /sys/fs/cgroup
/dev/mapper/centos-root   50G   39G   12G   78% /
/dev/sda2               1014M  176M  839M   18% /boot
/dev/sda1                200M   12M  189M    6% /boot/efi
/dev/mapper/centos-home  180G   33M  180G    1% /home
tmpfs                    1.6G     0  1.6G    0% /run/user/0
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b13ed87897fe1cabe547341e9a855c43bf04fcf7f3ef44e41138b08e62fb6191/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/502140d31ceae249f65f90e2fc096af6d8cece5f086ab9ce7e01ff80ec82576d/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b8bfb2a4f4360f9b3915452fb4303d5ebf02299bee754de9d7245b5efc0d8149/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/59d0f795fa7c6d89467ada62d8e9e1cd8b9ad5628ca251bb5c9011fbed513af1/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b7ed9b03a812579f993ac7dbe086afb15401ec5109af9467a5efbbc524f74b79/merged

备份/home数据

[root@mrf-server opt]# mkdir /home-backup
[root@mrf-server opt]# 
[root@mrf-server opt]# mv /home/* /home-backup

删除/home逻辑卷

[root@mrf-server /]# umount /home
[root@mrf-server /]# 
[root@mrf-server /]# lvremove /dev/centos/home
Do you really want to remove active logical volume centos/home? [y/n]: y
  Logical volume "home" successfully removed

查看可用大小

[root@mrf-server /]# vgdisplay
  --- Volume group ---
  VG Name               centos
  System ID             
  Format                lvm2
  Metadata Areas        1
  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                1
  Act PV                1
  VG Size               <237.28 GiB
  PE Size               4.00 MiB
  Total PE              60743
  Alloc PE / Size       14784 / 57.75 GiB
  Free  PE / Size       45959 / <179.53 GiB
  VG UUID               6zqmne-yIRi-DzR0-pOc7-pwHI-O1hM-Vh7T5c

根据：Free PE / Size 45959 / <179.53 GiB判断可用空间为：179.53 GiB

新建/home卷

[root@mrf-server /]# lvcreate -L 50G -n home centos
WARNING: xfs signature detected on /dev/centos/home at offset 0. Wipe it? [y/n]: y
  Wiping xfs signature on /dev/centos/home.
  Logical volume "home" created.

查看/home卷

[root@mrf-server /]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                PkUzOD-edvq-AYZH-RZte-nOOF-h27l-UDywl5
  LV Write Access        read/write
  LV Creation host, time localhost, 2024-05-07 16:07:38 +0800
  LV Status              available
  # open                 2
  LV Size                7.75 GiB
  Current LE             1984
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                jpAxQq-GFzU-AfaT-Hotn-k6bG-FwII-a6EzIq
  LV Write Access        read/write
  LV Creation host, time localhost, 2024-05-07 16:07:43 +0800
  LV Status              available
  # open                 1
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
   
  --- Logical volume ---
  LV Path                /dev/centos/home
  LV Name                home
  VG Name                centos
  LV UUID                jMNrQ0-VpnG-FBry-wmrb-9oue-ALSZ-fuXYrd
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2024-05-08 09:38:46 +0800
  LV Status              available
  # open                 0
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

分配50G空间成功

查看可用空间大小

[root@mrf-server /]# vgdisplay
  --- Volume group ---
  VG Name               centos
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               <237.28 GiB
  PE Size               4.00 MiB
  Total PE              60743
  Alloc PE / Size       27584 / 107.75 GiB
  Free  PE / Size       33159 / <129.53 GiB
  VG UUID               6zqmne-yIRi-DzR0-pOc7-pwHI-O1hM-Vh7T5c

根据：Free PE / Size 33159 / <129.53 GiB判断可用空间为129.53 GiB

/home上建立xfs文件系统

[root@mrf-server /]# mkfs -t xfs /dev/centos/home
Discarding blocks...Done.
meta-data=/dev/centos/home       isize=512    agcount=4, agsize=3276800 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=13107200, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=6400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0

挂载/home

[root@mrf-server /]# mount /dev/centos/home /home
[root@mrf-server /]# df -h
文件系统                 容量  已用  可用 已用% 挂载点
devtmpfs                 7.7G     0  7.7G    0% /dev
tmpfs                    7.7G     0  7.7G    0% /dev/shm
tmpfs                    7.7G   18M  7.7G    1% /run
tmpfs                    7.7G     0  7.7G    0% /sys/fs/cgroup
/dev/mapper/centos-root   50G   39G   12G   78% /
/dev/sda2               1014M  176M  839M   18% /boot
/dev/sda1                200M   12M  189M    6% /boot/efi
tmpfs                    1.6G     0  1.6G    0% /run/user/0
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b13ed87897fe1cabe547341e9a855c43bf04fcf7f3ef44e41138b08e62fb6191/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/502140d31ceae249f65f90e2fc096af6d8cece5f086ab9ce7e01ff80ec82576d/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b8bfb2a4f4360f9b3915452fb4303d5ebf02299bee754de9d7245b5efc0d8149/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/59d0f795fa7c6d89467ada62d8e9e1cd8b9ad5628ca251bb5c9011fbed513af1/merged
overlay                   50G   39G   12G   78% /var/lib/docker/overlay2/b7ed9b03a812579f993ac7dbe086afb15401ec5109af9467a5efbbc524f74b79/merged
/dev/mapper/centos-home   50G   33M   50G    1% /home

迁移home目录的备份数据

[root@mrf-server /]# mv /home-backup/* /home
[root@mrf-server /]# rm -rf /home-backup

将剩余的空间分配给根目录

[root@mrf-server /]#  lvextend -L +129G /dev/centos/root
  Size of logical volume centos/root changed from 50.00 GiB (12800 extents) to 179.00 GiB (45824 extents).
  Logical volume centos/root successfully resized.
[root@mrf-server /]# 
[root@mrf-server /]# 
[root@mrf-server /]# 
[root@mrf-server /]# 
[root@mrf-server /]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/centos/swap
  LV Name                swap
  VG Name                centos
  LV UUID                PkUzOD-edvq-AYZH-RZte-nOOF-h27l-UDywl5
  LV Write Access        read/write
  LV Creation host, time localhost, 2024-05-07 16:07:38 +0800
  LV Status              available
  # open                 2
  LV Size                7.75 GiB
  Current LE             1984
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1
   
  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                jpAxQq-GFzU-AfaT-Hotn-k6bG-FwII-a6EzIq
  LV Write Access        read/write
  LV Creation host, time localhost, 2024-05-07 16:07:43 +0800
  LV Status              available
  # open                 1
  LV Size                179.00 GiB
  Current LE             45824
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
   
  --- Logical volume ---
  LV Path                /dev/centos/home
  LV Name                home
  VG Name                centos
  LV UUID                jMNrQ0-VpnG-FBry-wmrb-9oue-ALSZ-fuXYrd
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2024-05-08 09:38:46 +0800
  LV Status              available
  # open                 1
  LV Size                50.00 GiB
  Current LE             12800
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:2

扩展根目录

[root@mrf-server /]# xfs_growfs /dev/centos/root
meta-data=/dev/mapper/centos-root isize=512    agcount=4, agsize=3276800 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=13107200, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=6400, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 13107200 to 46923776
[root@mrf-server /]# df -h
文件系统                 容量  已用  可用 已用% 挂载点
devtmpfs                 7.7G     0  7.7G    0% /dev
tmpfs                    7.7G     0  7.7G    0% /dev/shm
tmpfs                    7.7G   18M  7.7G    1% /run
tmpfs                    7.7G     0  7.7G    0% /sys/fs/cgroup
/dev/mapper/centos-root  179G   39G  141G   22% /
/dev/sda2               1014M  176M  839M   18% /boot
/dev/sda1                200M   12M  189M    6% /boot/efi
tmpfs                    1.6G     0  1.6G    0% /run/user/0
overlay                  179G   39G  141G   22% /var/lib/docker/overlay2/b13ed87897fe1cabe547341e9a855c43bf04fcf7f3ef44e41138b08e62fb6191/merged
overlay                  179G   39G  141G   22% /var/lib/docker/overlay2/502140d31ceae249f65f90e2fc096af6d8cece5f086ab9ce7e01ff80ec82576d/merged
overlay                  179G   39G  141G   22% /var/lib/docker/overlay2/b8bfb2a4f4360f9b3915452fb4303d5ebf02299bee754de9d7245b5efc0d8149/merged
overlay                  179G   39G  141G   22% /var/lib/docker/overlay2/59d0f795fa7c6d89467ada62d8e9e1cd8b9ad5628ca251bb5c9011fbed513af1/merged
overlay                  179G   39G  141G   22% /var/lib/docker/overlay2/b7ed9b03a812579f993ac7dbe086afb15401ec5109af9467a5efbbc524f74b79/merged
/dev/mapper/centos-home   50G   33M   50G    1% /home