[stevan]

> This seems like a problem you can’t solve generically and you always end up making trade offs.

That shouldn't stop us from solving the problem in the cases where it's possible though? We can tackle the corner cases separately with manual overrides.

> This is probably a big reason why most programs use external storage solutions even if they’re less efficient - it centralizes maintenance of state onto a system that has well defined semantics and can handle repair transparently.

This is certainly the case today, what I'm asking is: does it always have to be like that in the future?

[vlovich123]

I suspect that it’s impossible in the sense that the “possible” space will look like a distributed storage solution and the rest will look similar to graceful handoff of new connections to new version + shutdown of old version after some time (with forceful disconnect of sessions hanging around).

[stevan]

I give two examples of a stateful upgrade in Erlang/OTP in the motivation, neither rely on distributed storage.