[root@localhost ~]# umount /home/

[root@localhost ~]# lvremove /dev/mapper/centos-home

Do you really want to remove active logical volume centos/home? [y/n]: y

  Logical volume "home" successfully removed

[root@localhost ~]# lvextend -L +120G  /dev/mapper/centos-root

  Size of logical volume centos/root changed from 50.00 GiB ( extents) to 170.00 GiB ( extents).

  Logical volume centos/root successfully resized.

[root@localhost ~]# xfs_growfs /dev/mapper/centos-root

meta-data=/dev/mapper/centos-root isize=    agcount=, agsize= blks

         =                       sectsz=   attr=, projid32bit=

         =                       crc=        finobt= spinodes=

data     =                       bsize=   blocks=, imaxpct=

         =                       sunit=      swidth= blks

naming   =version               bsize=   ascii-ci= ftype=

log      =internal               bsize=   blocks=, version=

         =                       sectsz=   sunit= blks, lazy-count=

realtime =none                   extsz=   blocks=, rtextents=

data blocks changed from  to

[root@localhost ~]# lvcreate -L 47G -n home centos

  Logical volume "home" created.

[root@localhost ~]# mkfs.xfs  /dev/mapper/centos-home

meta-data=/dev/mapper/centos-home isize=    agcount=, agsize= blks

         =                       sectsz=   attr=, projid32bit=

         =                       crc=        finobt=, sparse=

data     =                       bsize=   blocks=, imaxpct=

         =                       sunit=      swidth= blks

naming   =version               bsize=   ascii-ci= ftype=

log      =internal log           bsize=   blocks=, version=

         =                       sectsz=   sunit= blks, lazy-count=

realtime =none                   extsz=   blocks=, rtextents=

[root@localhost ~]# mount  /dev/mapper/centos-home  /home

[root@localhost ~]# df -h

文件系统                 容量  已用  可用 已用% 挂载点

/dev/mapper/centos-root  170G  899M  170G    % /

devtmpfs                  63G        63G    % /dev

tmpfs                     63G        63G    % /dev/shm

tmpfs                     63G  9.5M   63G    % /run

tmpfs                     63G        63G    % /sys/fs/cgroup

/dev/sda2               1014M  135M  880M   % /boot

/dev/sda1                200M  9.8M  191M    % /boot/efi

tmpfs                     13G        13G    % /run/user/

/dev/mapper/centos-home   47G   33M   47G    % /home

[root@localhost ~]# lsblk

NAME            MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT

sda               :       223G   disk

├─sda1            :       200M   part /boot/efi

├─sda2            :         1G   part /boot

└─sda3            :     .8G   part

  ├─centos-root :       170G   lvm  /

  ├─centos-swap :         4G   lvm  [SWAP]

  └─centos-home :        47G   lvm  /home

sdb               :      .9T   disk

sdc               :      .9T   disk