It is absolutely possible to write a large stateful system from the ground up so that autonomous testing techniques can be applied to it. FoundationDB and Tiger Beetle are both examples of this, I think Resonate might be another one, and Toby Bell's talk at Strange Loop last year is a great guide on how to do so.
What's much harder is to take an arbitrary system, written in an arbitrary way, without these techniques in mind, and make it amenable to this sort of testing. From the start of our company, we believed that unless this was possible, the market would be too hard to crack, because most human beings are not very foresightful and not able to justify a bunch of extra work.
Hypervisor-based snapshot fuzzing like Nyx-Net and deterministic userspaces like Facebook's now-discontinued Hermit project are the other ways I know of accomplishing that goal. We believe that both of them have some pretty serious practical limitations which our approach does not share.
EDIT: Maybe the way to get to the crux of the disagreement is for me to turn the question around. Why do you believe that the vast majority of stateful and concurrent systems are not tested with fuzzing?
What's much harder is to take an arbitrary system, written in an arbitrary way, without these techniques in mind, and make it amenable to this sort of testing. From the start of our company, we believed that unless this was possible, the market would be too hard to crack, because most human beings are not very foresightful and not able to justify a bunch of extra work.
Hypervisor-based snapshot fuzzing like Nyx-Net and deterministic userspaces like Facebook's now-discontinued Hermit project are the other ways I know of accomplishing that goal. We believe that both of them have some pretty serious practical limitations which our approach does not share.
EDIT: Maybe the way to get to the crux of the disagreement is for me to turn the question around. Why do you believe that the vast majority of stateful and concurrent systems are not tested with fuzzing?