Resolved With Burst not deterministic, can we run the server on other platform than target platform? | Replay

Hey! Yes you can mix platforms. NetCode for Entities does benefit from full determinism, but it does not rely on it. Linux server Vs multiplatform client (including mobile) is the expected common workflow.

Mispredictions happen "all the time" even with good conditions, so don't worry about CPU arch divergences.

Unfortunately no, you'd need to store much more (exactly how much is game dependent). We're not a deterministic lockstep architecture, so input on each tick is not enough info to reproduce the frame. Storing a snapshot of the all ghost's GhostFields at 15/30/60Hz (or similar) is probably required.

 

Burst is not completely fully deterministic (floating point in particular) across architecture. It is somewhat on the same (x86 for example). The default settings (unless you put FloatMode: Fast) are to use no-optimisation, so madd and other reciprocal stuff aren't used.
NetCode for entities is not a GPPO or LockStep model where fully determism is required. True, client send the input to the server and the client-side "prediction" pretend to calculate the same simulation output.
But as I said, "it pretend". There it no guarateee the prediction to be 100% identical, there are multiple factors that affect that:
- float quantisation
- partial ticks
- partial ghost snapshots

That may cause the client to "mis-predict". But that does not matter. The simulation is "server authoritative", implying that the state from the server is the truth. The client will correct its output (and eventually slowly converge or snap to the new result) and stay in sync with server.

You can still store the input the server apply to tick X (what it saw and applied to the client) a file. And replay that back and getting the same simulation output for your player (on the same CPU architecture). It rmay requires though a little mode data than this (unless recorded at exactly the beginning of the simulation, where the initial state is known).
There are there little things that may be required to make this work exactly identical (some state for the time sync) but that should be.
However, that would work only if the client also simulates all the other entities too (that may be not the case, the server was doing that and the client just showing the interpolated data).