Increase docker pool size by changing storage driver

Configure Docker with the devicemapper storage driver

NOTE: This is for Docker CE & Docker EE

Issue:

By default you will notice that docker storage device is "brtfs" i.e. default storage, which is limited to 20GB of data storage.

Usually you will find this storage as too limited to use. As most of the times we have to install multiple images that too of high storage like 4/8/10GB. And with this default storage you will be end up getting frustrated.

Solution:

Configure Docker with "devicemapper" storage driver.

How to do this:

1) Stop Docker

$ sudo systemctl stop docker 

2) Edit /etc/docker/daemon.json. If it does not yet exist, create it. Assuming that the file was empty, add the following contents.

{
  "storage-driver": "devicemapper"
}

Note: Docker will not start if the daemon.json file contains badly-formed JSON

3) Start Docker

$ sudo systemctl start docker

4) Verify that the daemon is using the devicemapper storage driver. Use the docker info command and look for Storage Driver

Note: This host is running in loop-lvm node, which is not supported on production systems. This is indicated by the fact that the Data loop file and a Metadata loop file are on files under /var/lib/docker/devicemapper/devicemapper.

Useful link: Use device mapper storage driver

Hope this helps :-)
Enjoy :-)