I finally found something useful on docs.docker.com

https://docs.docker.com/engine/userguide/storagedriver/device-mapper-driver/

The steps I went thru for centOS 6

Lang: bash 
# service docker stop 
# puppet agent --disable 
# umount /var/lib/docker 
# rm -rf /var/lib/docker/* 
# lvcreate -L 450G -n data vg_db4new 
# lvcreate -L 10G -n metadata vg_db4new 
# echo 'other_args="--storage-driver=devicemapper --storage-opt dm.datadev=/dev/vg_db4new/data --storage-opt dm.metadatadev=/dev/vg_db4new/metadata --storage-opt dm.fs=xfs"' > /etc/sysconfig/docker
# service docker start

I originally tried to make metadata 20G, but that gave me errors.

For centOS7 on fresh aws install

https://docs.docker.com/engine/installation/centos/

Lang: bash 
# yum update
# yum install lvm2
# pvcreate /dev/xvdf
# vgcreate docker /dev/xvdf
# lvcreate -L 100G -n lib docker
# lvcreate -L 10G -n metadata docker
# lvcreate -L 880G -n data docker
# export EDITOR=vim
# systemctl edit docker