The mnesia_rocksdb backend plugin offers support for very large disk-based tables in mnesia. It also offers a low-level access API, enabling efficient use of the Rocksdb access APIs while using Mnesia as the management framework: Tables are created via Mnesia, and can be access either using the low-level API or the normal Mnesia API.
We at QPQ AG are improving mnesia_rocksdb, in a new location: