How to Host a Vault Hunters 3 Server

What Is Vault Hunters 3?

Vault Hunters 3 (also known as Vault Hunters: The Third Edition) is a unique modpack built on Forge for Minecraft 1.18.2, designed by the Iskall85 team. The core mechanic revolves around procedurally generated vault dimensions that players enter, loot, and escape from before a timer runs out. Progression unlocks new abilities, gear modifiers, and vault objectives. It blends roguelike dungeon crawling with Minecraft building and automation through mods like Create, Botania, Applied Energistics 2, and Refined Storage.

The vault dimension is the performance wildcard. Every time a player opens a vault, the server generates an entirely new dimension with custom structures, mobs, and loot. If you want to host a Vault Hunters 3 server for multiple concurrent players, you need hardware that can handle simultaneous dimension generation without TPS drops.

Server Requirements

Forge and Java Version

Vault Hunters 3 runs on Forge for Minecraft 1.18.2, requiring Java 17. The official server pack includes the correct Forge build. Java 8 will fail immediately, and Java 21 is untested with 1.18.2 Forge. Stick to Java 17.

RAM Allocation

Player Count	Minimum RAM	Recommended RAM
1–5 players	6 GB	8 GB
6–12 players	8 GB	10 GB
12–20 players	10 GB	12 GB

Each active vault dimension consumes memory for its structures, entities, and loot tables. When five players each run vaults simultaneously, memory usage spikes. Size your plan generously and use the RAM calculator when planning to host a Vault Hunters 3 server.

Downloading and Installing

Download the Vault Hunters 3 server pack from CurseForge or the official Vault Hunters website. Extract and run:

chmod +x startserver.sh
./startserver.sh

Accept the EULA, restart, and wait for the first boot to complete (3 to 5 minutes). The Vault Hunters mod generates its initial configuration, vault pool data, and skill trees during this phase.

Config Tweaks

Vault Timer and Difficulty

The vault timer controls how long players have inside each vault. The default is balanced for the intended difficulty, but you can adjust it in the Vault Hunters config. Extending the timer makes vaults more forgiving, reducing it increases the pressure. Some community servers add 30 seconds to help newer players.

Vault Dimension Cleanup

After a player exits or fails a vault, the generated dimension should be cleaned up. Verify that old vault dimensions are being deleted properly by checking the world folder for stale dimension data. Leftover vault worlds consume disk space and can slow restarts.

Common Issues

Concurrent Vault Generation Lag

When multiple players enter vaults at the same time, the server generates multiple dimensions simultaneously. This is extremely CPU-intensive. On underpowered hardware, TPS drops to single digits during generation. Stagger vault entries if possible, or use a high-clock-speed host to handle the burst.

Skill Tree Corruption

Rare server crashes during vault completion can corrupt a player's skill tree data. Keep daily backups of the world save, specifically the the_vault/ data folder. Restoring from backup is the most reliable fix for corrupted player data.

Performance Tuning

Set view-distance=8 and simulation-distance=6. Vault dimensions are compact, so tight simulation distances work well inside them. The overworld benefits from the same settings since players build bases with machines.

JVM flags for Java 17:

java -Xms6G -Xmx8G -XX:+UseG1GC -XX:MaxGCPauseMillis=130
-XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=40
-XX:G1MaxNewSizePercent=50 -XX:G1HeapRegionSize=16M
-XX:G1ReservePercent=15 -XX:InitiatingHeapOccupancyPercent=20
-XX:+AlwaysPreTouch -jar forge-server.jar nogui

NVMe storage matters for Vault Hunters because vault dimensions write large amounts of chunk data on creation. Slow disks turn a 2-second generation into a 10-second lag spike. Review our JVM flags guide for full explanations. For similar Forge packs, see our ATM9 guide or the Create mod guide.

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