Explore alternatives to device mapper storage driver for Docker.

[smrubin]

The device-mapper storage driver with docker doesn't clean up after itself well enough and appears to have a memory leak, see GitHub issue here: moby/moby#3182 (comment).

We should explore an alternative to the device-mapper, such as AUFS or Overlay and use that instead in our environments to keep them lean.

[bamb00]

Is this target to loop-lvm and direct-lvm?

[smrubin]

Right now loop-lvm is being used with devicemapper. If we want to continue using devicemapper, we should configure direct-lvm for production.

Although, I am not opposed to investigating overlay2 or aufs in place of devicemapper, as those are recommended in the docs and are suitable for our environment.