A VM/docker are different things, but when you use the Docker CLI you **may** also be using a VM underneath too. I agree with you that Docker is just the latest fad, and has lots of issues. I am using it to easily distribute a CLI: `docker run x` will work on Mac, Linux and Windows, each having their own set up of VM's etc that I do not need to configure. I also want to use it as a basic sandbox. As I understand, **when the host is Linux, and the guest is Linux, the process runs as if it just a normal Linux-host process**, just with extra sandbox-like protections applied to the process. **In the basic cases I tested, WAL mode seems to work fine here** (I guess because the mmap memory is managed by the single Linux-host). When the host is Mac OS or Windows, a VM is used like this (which breaks WAL): [Mac OS docker levels](https://news.ycombinator.com/item?id=25454121)