Related, "The Design & Implementation of Sprites" [1] (also currently on the front page) mentioned JuiceFS in its stack:

> The Sprite storage stack is organized around the JuiceFS model (in fact, we currently use a very hacked-up JuiceFS, with a rewritten SQLite metadata backend). It works by splitting storage into data (“chunks”) and metadata (a map of where the “chunks” are). Data chunks live on object stores; metadata lives in fast local storage. In our case, that metadata store is kept durable with Litestream. Nothing depends on local storage.

[1] https://news.ycombinator.com/item?id=46634450