Running all tests in my current project takes some time. With 26 GB of free memory, why not use it for something useful? tmpfs is one way to speed up the test execution. A common approach is to work directly in a tmpfs folder and backup your work to a folder on disk with cron. I found this setup a bit complicated and error prone. I never really trusted my own setup on boot time and with cron. Now I use a much simpler setup that is not using cron at all.