Yes you need to make sure all your modifications lead to consistent states. If you don't do this, then you end up with inconsistent states and depending on your

Yes you need to make sure all your modifications lead to consistent states. If you don't do this, then you end up with inconsistent states and depending on your app deadlocks. Then it would only be useful as a cache and even then only if the temporary inconsistencies were tollerable. Using a datastore without guaranteeing (and be it only eventual) consistency is calling for trouble for any data that is worth something. Redis CAN be used for many things, but it's not always trivial to do it right even though at first glance it might look so and most web developers are lazy or just don't know better.