Another interesting option would be the Dat Project. I just recently learned about it. https://datproject.org/.
kbfs, the Keybase File System, I learned a little more about it: it is using Fuse, and, there are a couple of characteristics to note. It is set up to sync dynamically, based on how much space there is on your drive. In this, it is somewhat similar to Google’s Drive system, “Google File Stream”, which syncs files when you need them, them backs off when you’re not accessing them.
You can force a permanence though, and cause
kbfs to sync a specific folder always, with something like:
keybase fs sync enable /keybase/private/rickcogley/path/to/my/codebook
I have not yet tried working this out yet, but the info is relevant I think.