So fork time is actually O(1) with VM size, its 500ms even for 64gb + disk. We're using some pretty weird COW techniques to pull it off.
Like with 10ms then online replication/backup — analogus to litestream for sqlite — but for in memory processes becomes feasible, no?
We have another set of optimizations that we believe can take us to ~200ms in the next few months but beyond that we're pretty much completely stuck.
Realistically other sandboxes will be able to get there before us because we've chosen to support so much of Linux/if you don't run an operating system or don't support custom snapshots that is much easier.
We are researching systems of hot moving VMs across VMs but it would have very different performance characteristics.
Our tech is not decades old so there is a chance we've missed something but our layer management is atomic so I'd be shocked if you'd be able to corrupt state across forks/snapshots.