The author of the original blog is confusing the issue of base-image of a Docker image and the host OS on which the Docker daemon is running. They are completely orthogonal issues. Yes, there've been plenty of complaints about DM performance and space reclamation issues. By all means, switch the host OS from CentOS/Fedora to Ubuntu if it alleviates the problems. The base-image is a completely different matter. There is no reason to switch from CentOS/Fedora to Ubuntu just because you changed the host OS. This is point of the filesystem isolation Docker provides.