What is a game server, really?

The word "server" gets used for everything: the dedicated machine, the program running on it, the place players connect to, the Discord server. They're not all the same thing.

This article is the actual concept, explained without jargon.

The basic model: client and server

When you play a single-player game, your computer does everything: simulating the world, running the physics, drawing the graphics, responding to inputs.

When you play a multiplayer game, the work splits between two roles:

The server holds the truth. Your client renders it. When you place a block, the client guesses (predicts) that the block appears. The server confirms or rejects. The server is authoritative.

Why one authoritative source

In a multiplayer game, multiple players are taking actions simultaneously. Without a central decider:

• Player A says "I picked up the diamond." Player B says "I picked it up first." Who has it?
• Player C punched the mob. The mob died (in their view). But the mob is still alive in your view. Who's right?
• Two players are at the same spot. Are they overlapping? Touching? Inside each other?

The server resolves all this. It maintains the canonical state. Every client respects it.

What "the server" actually is

Practically, three things hide behind the term:

1. The physical machine. A computer in a data center somewhere. Or your home PC. Or a rented VPS.

2. The server software. A program running on that machine. For Minecraft: the Java server jar. For Valheim: the dedicated server tool. For Eco: the EcoServer executable. This program does the simulation.

3. The "world" or "instance." A specific game running on that software, with specific state, specific players. A Minecraft "server" colloquially means a specific world / community / game-in-progress.

When someone says "the server is laggy," they could mean any of these. Usually they mean the running game world is sluggish.

The relationship to other "servers"

The word "server" is reused across computing:

• Web server: a program that serves web pages.
• File server: a program that stores and serves files.
• Database server: a program that holds structured data.
• Game server: what we've been discussing.

All "servers" because they wait for clients to connect and provide some service. The underlying machines and protocols differ.

Discord "servers" are technically a Discord-specific concept (more like community channels). The word "server" stuck for historical reasons.

Hosting a server

Running game server software requires:

• A computer to run on.
• An operating system (usually Linux for paid hosting; self-hosters use Linux, Windows, or macOS).
• The actual game server software.
• A network connection allowing inbound traffic on specific ports.

Options:

• Rent from a host. Pay monthly, they handle hardware. Most common for community servers.
• Self-host on your PC. You provide the hardware. See the self-hosting article for trade-offs.
• Rent a generic VPS. Cheap general-purpose server. You install the game server software yourself.

Each has trade-offs covered elsewhere in this blog.

What's actually inside a game server

Different games structure this differently, but typical components:

Component	What it does
World state	Current snapshot: terrain, players, mobs, blocks, items
Game loop	The tick: simulate one step of the world
Network handler	Receives packets, sends responses
Save system	Periodically writes state to disk
Authentication	Verifies player identities
Plugin / mod system	Allows extensions to modify behavior

Each of these has its own challenges. Tick handling is the main performance concern. Saving creates I/O spikes. Authentication is a security concern.

What the server "owns"

The server is responsible for:

• The world's state (blocks, mobs, items, weather).
• The simulation (physics, AI, time progression).
• Authoritative validation (was that block placeable? was that movement legal?).
• Persistence (saving everything to disk).
• Player accounts and permissions on the server.

The client handles:

• Rendering (drawing what the world looks like).
• Input (turning your keyboard / mouse into game actions).
• Local prediction (showing your character moving immediately, even before the server confirms).
• Particle effects, sound, UI.

Cross-platform multiplayer (Java + Bedrock) is hard because the two clients render differently and have different physics, even when they share a server.

Performance: where servers struggle

Game servers' performance bottleneck is usually:

• CPU time per tick. Each tick has a budget. Exceed it, the world slows down.
• RAM. Holding all the active world state in memory.
• Disk I/O. Saves and chunk loads.
• Network. Bandwidth and latency to players.

Different games stress these differently. Minecraft is CPU-heavy on a single core. Valheim is networking-stressed at scale. Eco is comprehensive simulation.

When the server fails

Common failure modes:

• Crash. The process dies. Players disconnect. Need restart.
• Hang. The process is alive but stuck. Similar effect.
• Slowdown. The process is alive but slow. Players experience lag.
• Out of memory. Process killed by OS for using too much RAM.
• World corruption. State on disk is damaged. Server can't start.

Most are recoverable. Backups make even the worst case manageable.

A server is a place

A useful framing: a multiplayer game server is less like a piece of software and more like a place. It has:

• A history (what's been built, who's been here).
• A culture (norms, in-jokes, rules).
• Members (regulars, newcomers, departed).
• An admin (someone who maintains it).

This framing matters because it shapes how you think about the server. A server isn't just a thing you boot; it's a community asset. Treat it like one.

The economics of running one

For one server:

• Hardware cost (rent or purchase).
• Bandwidth cost (usually included with hosting).
• Time cost (your hours administering).
• Social cost (the moderation work).

For most communities of 10 to 30 players, the dollar cost is $10 to $20 a month. The time cost is highly variable, from "0 if everything works" to "12 hours during an incident."

For larger communities, costs scale. For smaller communities, often a single payer covers everything.

A common confusion: server vs realm

Microsoft's "Minecraft Realms" is a hosted server-with-no-knobs. Easy for non-technical users. Limited capacity. Modest customization.

A "Minecraft server" (lowercase generic) is more flexible: any host, any modpack, any plugins.

Realms is a server, technically. But when people say "I rented a server," they usually mean dedicated paid hosting with full configuration access, not Realms.

Conclusion

A game server is a program running on a computer somewhere, maintaining the authoritative state of a multiplayer game world. It's also (colloquially) the community of players inhabiting that world.

The technical and social meanings are both real and both important. If you're going to run one, understand both. The hardware will mostly take care of itself with good hosting. The community needs your attention.

A server is a place. Tend to it.