I'm bringing overlayfs to people at my company to save time on a lenghty CI process, and they are in awe at the speedup. But after demo-ing it to a few people I realized they could just use / (I could have brought them) docker.
Huge (32gb) git repo full of junk and small files. No power to change it. Created a cron job that updates and rebuilds every 24hrs. Clients can clone it instantly with overlay instead of a 30m checkout and build each time. Not to mention disk space savings
