Reduce an LVM partition on CentOS 7

reduce-lvm-partition-centos-7.md

Reduce LVM Partition on CentOS 7

Sometimes when creating a new CentOS 7 server, the drive is partioned with the root, boot and swap, and then all the rest of the space is given to the home directory.

Here, we are going to reduce the size of the /home partition and allocate the remaining space back to the root partition.

List Block Devices

List the current block devices

lsblk

It should look like this

NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0  1.1T  0 disk
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0  1.1T  0 part
  ├─centos-root 253:0    0   50G  0 lvm  /
  ├─centos-swap 253:1    0    4G  0 lvm  [SWAP]
  └─centos-home 253:2    0    1T  0 lvm  /home
sr0              11:0    1 1024M  0 rom

Backup /home

Backup the contents of the /home directory

tar -czvf /root/home.tgz -C /home .

Test the backup

tar -tvf /root/home.tgz

Reduce the Size of the /home Partition

Unmount home

umount /dev/mapper/centos-home

[OPTIONAL] Incase the target is busy.Login as my normal user, switch to root and closed your own session like this:

ssh myuser@myvm

cd /
exec sudo su

Remove the home logical volume

lvremove /dev/mapper/centos-home

Recreate a new 80GB logical volume for /home

lvcreate -L 80GB -n home centos

Format it

mkfs.xfs /dev/centos/home

Mount it

mount /dev/mapper/centos-home

Extend /root volume

Extend the /root volume with all of the remaining space and resize the filesystem

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

Restore /home

Restore the contents of the /home directory

tar -xzvf /root/home.tgz -C /home

List Block Devices

List the block devices again to make sure it was updated

lsblk

It should look like this

NAME            MAJ:MIN RM    SIZE RO TYPE MOUNTPOINT
sda               8:0    0    1.1T  0 disk
├─sda1            8:1    0      1G  0 part /boot
└─sda2            8:2    0    1.1T  0 part
  ├─centos-root 253:0    0 1012.8G  0 lvm  /
  ├─centos-swap 253:1    0      4G  0 lvm  [SWAP]
  └─centos-home 253:2    0    100G  0 lvm  /home
sr0              11:0    1   1024M  0 rom