Currently yes. If your state doesn't fit in memory on the number of machines you have, you'd need to add more.

We plan on adding support for only keeping part of state in memory. That's in the discussion phase. We want to talk to folks about their use cases and ideally work with them before adding it.

There are many trade-offs involved in such a feature and making those trade-offs based on informed decisions of our possible users needs is our preferred solution.