Move system directory to other drive
For this example, i'm moving /home directory to another drive:
# enter in rescue mode systemctl isolate rescue.target # Mount the other drive mount -t ext4 -o sync /dev/sdb1 /mnt # move all data from /home/ folder to the other drive # and ensure that all data are written to the disk mv /home/* /mnt/ && sync # fetch the uuid of the other drive lsblk -o UUID,LABEL,MOUNTPOINT,SIZE /dev/sdb1
then in /etc/fstab, add a line to auto mount the other drive as /home directory
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx /home ext4 auto,nouser,defaults,nodev,relatime 0 0
then reboot and voilà!