Optimizing Proxmox VE for Low-Latency Game Hosting (Geometry Dash-Style Server)

[luizamarns]

Hi everyone,


I’m currently setting up a Proxmox VE server and experimenting with hosting a lightweight rhythm/arcade style game server (similar to Geometry Dash Unlocked) for a small group of friends. The idea is to keep things smooth, low-latency, and secure without overcomplicating the setup.


Right now, my environment looks like this:

• Latest Proxmox VE installed
• A mix of VMs and LXC containers
• Dedicated VM with a public IP for the game server
• Proxmox firewall enabled (default configuration so far)

I’ve done some initial testing (including running modified/unlocked builds of the game for stress testing), and performance is decent, but I want to tighten things up especially around latency and network stability.


I’d really appreciate advice on a few things:

• Best network setup for lightweight multiplayer game hosting on Proxmox (bridge vs NAT, etc.)
• Recommended firewall rules to allow required traffic while keeping the VM secure
• Any tuning tips for reducing latency or improving packet handling
• General best practices when hosting small game servers in a virtualized environment

Not aiming for anything massive just a clean, reliable setup for casual online play.


Thanks in advance!

 

[leesteken]

Make sure never to hit anywhere near 100% on any resource otherwise you'll get increased latency and (micro) stutters.Probably best to ignore Hyperthreads and SMT (and only count real cores). Virtualization is usually trying to do the opposite of what you seem to want.

EDIT: Memory (RAM) bandwidth is shared between all your VM/CTs, this will increase latency when more than one VM is busy. Best to use a server platform with (many) more than 2 memory channels (and as many DIMMs).

 

[luizamarns]

Make sure never to hit anywhere near 100% on any resource otherwise you'll get increased latency and (micro) stutters.Probably best to ignore Hyperthreads and SMT (and only count real cores). Virtualization is usually trying to do the opposite of what you seem to want.

EDIT: Memory (RAM) bandwidth is shared between all your VM/CTs, this will increase latency when more than one VM is busy. Best to use a server platform with (many) more than 2 memory channels (and as many DIMMs).

Thanks, that actually makes a lot of sense.


I was already trying to keep resource usage low, but I didn’t fully consider how quickly latency can spike once things get close to 100%. I’ll definitely aim to leave more headroom instead of pushing the VM too hard.
Good point about hyperthreading/SMT as well I was counting logical cores, but I’ll switch focus to physical cores only and test again.
The RAM bandwidth part is interesting. Right now I’m on a fairly standard setup with limited memory channels, so that could explain some of the small stutters I noticed during testing when multiple containers were active.
I might try isolating the game server a bit more (CPU pinning / reducing background load) and see how much that improves consistency.


Appreciate the insight

 

[Fearless-Grape5584]

Since you're focused on a clean, reliable setup without overcomplicating things, here's my take — especially on the network and security side, which hasn't been covered much in this thread.

Network isolation first
With a public-facing game server VM, the main thing I would care about is blast-radius containment. If that VM is compromised, you do not want it to become a path into your other VMs, containers, or the Proxmox management network.

For a small setup, I would avoid putting pfSense/OPNsense in the datapath unless you actually need router/firewall features from them. A plain Linux bridge with VirtIO is usually the simpler and lower-overhead choice for latency-sensitive hosting.

That said, using a separate bridge alone is not a complete security boundary. It helps separate L2 traffic, but I would still combine it with Proxmox firewall rules so the game VM cannot reach your management network or other internal VM networks.

If you want a more structured version of that approach, Proxmox SDN VNets are a good fit. You can put the game server into its own isolated VNet and enforce boundaries with the Proxmox firewall/nftables instead of adding another router VM.

Firewall basics
At minimum, I would allow inbound traffic only to the UDP/TCP ports the game server actually needs, block inter-VM traffic by default, and make sure the Proxmox host management interface is not reachable from the game server network.

For latency
Bridge mode rather than NAT is the right direction. VirtIO NIC, CPU type host, leaving CPU headroom, and optionally CPU pinning/isolation are also worth testing. Avoiding CPU/RAM contention is probably more important than trying to add more network appliances.

If you later want to automate this kind of Proxmox SDN isolation, there is an open-source script called MSL Setup that creates isolated VNets and firewall rules for project/lab-style environments. It may be overkill for a single casual game VM, but it becomes useful if you add more public-facing or semi-trusted VMs later.