Pre-Generating Your World With Chunky
Pre-generate your Minecraft world with Chunky to eliminate exploration lag — setting a world border, choosing a radius, running it safely and estimating disk space.
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World generation is one of the most expensive things a Minecraft server does. When a player walks into terrain nobody has visited, the server must generate it — terrain, caves, structures, features — on the fly. A few players exploring in different directions can drag TPS down for everyone. Pre-generating the world removes that cost from gameplay entirely. Chunky is the standard tool for the job.
Why pre-generation helps
Loading an existing chunk from disk is far cheaper than generating a new one. Pre-generation does all the expensive generation work up front, while nobody is playing. After that:
- Exploration loads chunks instead of creating them, so TPS stays stable.
- Elytra flights and fast travel stop causing lag spikes.
- Map plugins (like BlueMap or Dynmap) can render the full world.
- You know exactly how much disk space the world takes.
It pairs naturally with a world border, so players can’t wander beyond the pre-generated area into expensive new terrain.
Install Chunky
Chunky is available for Paper/Spigot (plugin), Fabric and Forge/NeoForge (mod). Download the right build from Modrinth or Hangar and place it in plugins/ or mods/, then restart.
Step 1: Decide on a size
Choose a radius (in blocks) from the centre of your world. Bigger isn’t always better — it takes longer to generate and uses more disk space.
| Server | Suggested radius | Area |
|---|---|---|
| Small friends server | 2,000–3,000 blocks | 4,000–6,000 blocks across |
| Community survival | 5,000 blocks | 10,000 blocks across |
| Large survival | 10,000 blocks | 20,000 blocks across |
The Nether is traversed at 8× the speed of the Overworld, so a Nether radius around one-eighth of your Overworld radius covers the matching area. The End needs little pre-generation unless players build far out on the outer islands.
Step 2: Set a world border
Set the border to match the area you’ll generate. With vanilla commands:
/worldborder center 0 0
/worldborder set 10000
That creates a 10,000-block-wide border (a radius of 5,000). Chunky also has its own border feature if you prefer.
Step 3: Configure and start Chunky
From the console or in-game (as an operator):
/chunky world world
/chunky center 0 0
/chunky radius 5000
/chunky start
worldselects which world to generate (repeat forworld_netherwith a smaller radius).shapedefaults to square;/chunky shape circlematches a circular border.- Chunky reports progress, speed and an estimated time remaining in the console.
Useful controls:
/chunky pause # pause generation
/chunky continue # resume after a pause or restart
/chunky cancel # stop and discard the task
Chunky remembers its progress, so a restart doesn’t lose work — use /chunky continue afterwards.
Step 4: Run it at the right time
Pre-generation uses a lot of CPU and disk. Run it:
- Before launch, when the server is empty — ideal.
- Overnight or during your quietest hours on an existing server.
- With players online only if necessary. Chunky lets you limit its speed so the server stays playable, but expect some impact.
On a modest server, generating a 5,000-block radius can take anywhere from a few hours to much longer depending on CPU speed, storage and whether mods add expensive terrain. Fast single-core performance and NVMe storage make a big difference.
Step 5: Check the disk space
A pre-generated world takes real space. As a rough guide, vanilla-style terrain for a 5,000-block radius (10,000 × 10,000 blocks) often lands in the low tens of gigabytes; modded terrain can be considerably more. Before starting, check you have enough free space for the world plus backups — daily backups of a large world multiply the storage you need. See Minecraft server backups.
If space is tight, start with a smaller radius and expand the border and pre-generation later as your community grows.
Updating Minecraft versions
When a new Minecraft version changes world generation, existing chunks keep their old terrain, and new terrain appears only in newly generated chunks. Pre-generated worlds therefore won’t show new features in areas already generated. Some servers expand the border after a major update so players can find new biomes and structures in fresh terrain. Updating your server to a new Minecraft version safely covers the details.
Tips for smooth generation
- Back up first if you’re pre-generating an existing world.
- Lower
view-distancetemporarily if players are online during generation. - Watch memory — generation uses extra memory; spark’s
/spark healthshows usage. - Generate the Nether too, with a radius about one-eighth of the Overworld’s.
- Don’t delete Chunky’s task files mid-run if you want to resume.
Common problems
Generation is very slow — CPU-bound (often a slow core or a heavy modpack), or storage is slow. Check with spark.
The server runs out of memory during generation — lower Chunky’s concurrency or speed, or allocate more RAM temporarily.
Players are getting lag while it runs — pause Chunky during busy hours and continue later.
The disk filled up — stop Chunky, free space, and shrink the radius.
Hosting
Kerit Cloud’s Minecraft servers run on high single-core-performance CPUs with NVMe storage — exactly what makes pre-generation and later chunk loading fast — and storage is sized to your world and backup retention as part of your custom quote (typically 10–100 GB). If you’re planning a large pre-generated world, mention the radius when you request a quote so the storage fits.
Summary
Pre-generating with Chunky moves world generation out of gameplay, eliminating the biggest cause of exploration lag. Choose a radius that fits your community, set a matching world border, run /chunky radius and /chunky start for each world — with the Nether at about one-eighth of the Overworld radius — during quiet hours, and check disk space for the world and its backups. Expand later as your community grows.