How to create private docker registry with existing mount?

Hi All

Docker newbie.
We learn that we need to create a private docker registry to store images in a private network.
We like to have a private docker registry set up on our Oracle Linux host.
Current setup are as follows:

Filesystem Size Used Avail Use% Mounted on
/dev/xvdb1 25G 17M 24G 1% /var/lib/docker
/dev/xvdb2 213G 13G 200G 7% /test

blkid
/dev/xvdb1: UUID=“bbbbbbbb-bbbb-bbbb-bbb-bbbbbb” UUID_SUB=“ccccccc-cccc-ccc-cccc-cccccccccc” TYPE=“btrfs”
/dev/xvdb2: UUID=“aaaaaaa-aaaa-bbbb-bbbb-aaaaaaaaaaaa” TYPE=“ext4”

We need detailed steps to

- increase the docker root disk space from 25GB to 35GB transferring some disk space from  /test

- create a disk space of 120GB of /var/lib/registry transferring some disk space from /test

Any help is appreciated.
Thank you