For those interested in an alternative to Redis on disk, compatible with the Redis protocol, have a look on Kvrocks[1] which was recently accepted in the Apache foundation. It is based on RocksDB and works quite nicely for us.
Thanks for this, it seems to even support redis' lua functionality with is essential for us. I wish I hadn't decided to use redis stack since even kvrocks isn't compatible with its extensions
[1]: https://github.com/apache/kvrocks