Hi Kelsey!

Well, native filesystem support for Docker on OSX is a little sluggish. This can make applications running in dev mode slow because they’re reloading a lot of files all the time.

Docker supports the NFS filesystem now, so this setup works by synchronizing a directory on OSX with another directory inside a running Docker container. The NFS service on OSX takes care of notifying Docker of changes on your host operating system, and the Docker NFS code notifies of changes in the other direction.

NFS itself is designed for synchronizing data across IP networks, but it does just as well here running on a single machine.

Hope that helps!