How to move disk space from centos-home to centos-root

I have a VM with 1 280GB disk. For some reason my layout is:

$ df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root   50G   21G   30G  41% /
devtmpfs                 5.8G     0  5.8G   0% /dev
tmpfs                    5.8G     0  5.8G   0% /dev/shm
tmpfs                    5.8G  8.5M  5.8G   1% /run
tmpfs                    5.8G     0  5.8G   0% /sys/fs/cgroup
/dev/mapper/centos-home  224G   13G  212G   6% /home
/dev/sda1                497M  145M  352M  30% /boot
tmpfs                    1.2G     0  1.2G   0% /run/user/1000

Running fdisk -l:

$ sudo fdisk -l
[sudo] password for admin:

Disk /dev/sda: 300.6 GB, 300647710720 bytes, 587202560 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: 0x0006c283

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1026047      512000   83  Linux
/dev/sda2         1026048   587202559   293088256   8e  Linux LVM

Disk /dev/mapper/centos-swap: 6316 MB, 6316621824 bytes, 12337152 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/centos-root: 53.7 GB, 53687091200 bytes, 104857600 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/centos-home: 240.1 GB, 240115515392 bytes, 468975616 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

And:

$ sudo lsblk -io NAME,TYPE,SIZE,MOUNTPOINT,FSTYPE,MODEL
NAME            TYPE   SIZE MOUNTPOINT FSTYPE      MODEL
fd0             disk     4K
sda             disk   280G                        Virtual disk
|-sda1          part   500M /boot      xfs
`-sda2          part 279.5G            LVM2_member
  |-centos-swap lvm    5.9G [SWAP]     swap
  |-centos-root lvm     50G /          xfs
  `-centos-home lvm  223.6G /home      xfs
sr0             rom   1024M                        VMware IDE CDR10

How do I move the disk space used for /dev/mapper/centos-home to /dev/mapper/centos-root? Do I have to shrink centos-home and reallocate to centos-root?

Solution 1:

You can reduce your home LV as long as it's unmounted. (please keep in mind that shrinking has some risks )

Go like this:

umount /dev/mapper/centos-home
lvreduce -L 200G /dev/mapper/centos-home

Mount back your home partition as you're done with it.

Then just extend your root volume.

lvextend -t -r -l+100%FREE /dev/mapper/centos-root

-t is test, if it's ok just run the command a second time without -t

Solution 2:

I forced the unmount by using the command sudo umount -fl /home

then carried on with those instructions.

Solution 3:

The answer gave by runyoufreak helped me a lot.

I would like to add a tip because when I finished the process of resize partitions, my Cent OS after of a reboot turned on emergency mode. At my case I am not using /home so I commented the partition at /etc/fstab. After that I could to boot my system.