Move MySQL data to /home on Debian

This may be blocked by the MariaDB service. To fix correctly override the service file with a local copy:

sudo cp /lib/systemd/system/mariadb.service /etc/systemd/system

Edit /etc/systemd/system/mariadb.service and change ProtectHome to be false (ProtectHome=false). Save the file

sudo systemd daemon-reload # refresh the systemd services so it sees your override file
sudo systemctl start mysql # and it should finally start