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Pre-generate the world

Generate chunks once, before players explore them. That is the difference between a smooth SMP and constant lag spikes.

1 min readUpdated 2026-09-14Diese Anleitung auf Deutsch lesen →

Generating a new chunk is one of the most expensive things a server does. When ten players explore in different directions at once, TPS tanks. Pre-generating does the work in advance, while nobody is playing.

With Chunky (Paper, Fabric, Forge)

  1. Install Chunky from the *Plugins*/*Mods* tab.
  2. Decide on a size. A 5000-block radius (10 000 × 10 000) is plenty for a 20-player SMP and takes a few hours.
  3. Set a world border so nobody walks off the pregenerated area: worldborder center 0 0 then worldborder set 10000.
  4. In the console: chunky radius 5000 then chunky start. Do this at night; the server is busy while it runs. chunky pause / chunky continue if players are on. chunky progress shows the status.
  5. Repeat for the Nether: chunky world world_nether, chunky radius 625 (the Nether is 1/8 scale), chunky start.

Disk space

Roughly 1 GB per 2500-block radius for the Overworld. Check your disk before starting; upgrade in the dashboard if needed.

After a Minecraft update

New versions add new terrain features only to new chunks. Pre-generated areas keep the old look. If you want the new stuff, expand the border outward rather than regenerating.