The Atomic host is a minimal distribution and, as such, is distributed on a 6 GB image to keep the footprint small. This is very less amount of storage to build and store lots of Docker images, so it is recommended to attach external storage for those operations.
By default, Docker uses /var/lib/docker
as the default directory where all Docker-related files, including images, are stored. In Project Atomic, we use direct LVM volumes via the devicemapper backend to store Docker images and metadata in /dev/atomicos/docker-data
and /dev/atomicos/docker-meta
respectively.
So, to add more storage, Project Atomic provides a helper script called docker-storage-helper
to add an external disk into the existing LVM thin pool. Let's look at the current available storage to Docker with the docker info
command:
As we can see, the total data space is 2.96 GB and the total metadata space is 8.38 MB.