Goal: I want to move my existing Docker data to new location (/mnt/Data), for more free space.

Solution:

1. Stop Docker service
   sudo systemctl stop docker

2. Edit /etc/docker/daemon.json and insert this

{
    "graph": "/mnt/Data/docker"
}

1. Move old data to new location
   sudo rsync -aqxP /var/lib/docker /media/Data/

2. Temporary move old data to other directory
   sudo mv /var/lib/docker /var/lib/docker.old

3. Start docker service
   sudo systemctl start docker

4. Check new config work
   docker info | grep -i root This should output new location

5. Remove old data

6. Profit

P/s: I'm using Docker version 20.10.6, build 370c289