When players explore new areas on a Minecraft server, the server has to generate new chunks in real time.
On modded servers, especially servers using world generation mods such as Tectonic, this can sometimes cause short lag spikes or console messages like:
Can't keep up! Is the server overloaded?
One way to reduce this is by using a tool called Chunky.
Chunky is a Minecraft chunk pre-generation tool.
Instead of the server generating chunks while players are exploring, Chunky can generate a selected area of the world in advance.
This can help reduce lag caused by:
Chunky can use extra server resources while it is running, so we recommend using it when no players are online.
While Chunky is generating chunks, you may still see temporary messages such as:
Can't keep up! Is the server overloaded?
This is normal while Chunky is actively generating chunks.
Once the task is finished, exploring inside the generated area should feel smoother.
How you install Chunky depends on the type of Minecraft server you are running.
If your server uses Paper, Spigot or Purpur, you can usually install Chunky through the server panel Plugin Manager if available.
You can also install it manually by uploading the Chunky plugin file to:
/plugins
Then restart your server.
If your server uses Forge, NeoForge or Fabric, we recommend installing Chunky manually.
The Plugin Manager may install a generic chunky.jar file, but this may not load correctly on modded server types.
For modded servers, download the correct loader version from Modrinth and upload it manually.
Steps:
.jar file/mods folderchunky in the console to check it loadedFor Forge, NeoForge and Fabric servers, upload Chunky to:
/mods
Do not upload the Paper/Spigot plugin version into /mods unless the file specifically supports your mod loader.
If the chunky command is not recognised after restarting, Chunky has probably not loaded correctly or the wrong version was installed.
These commands can be run from your server console.
chunky
This should show the Chunky command list. If this command is not recognised, Chunky has not loaded correctly.
chunky world overworld
This sets the centre of the area you want to generate.
For world spawn or coordinates 0 0, use:
chunky center 0 0
If your base is somewhere else, use the base coordinates instead.
Example:
chunky center 250 -800
A square shape is simple and works well for most servers:
chunky shape square
Start with a sensible radius first.
For a small test:
chunky radius 500
For a good starting area around spawn or a base:
chunky radius 1000
A 1000 block radius means Chunky will generate roughly 1000 blocks in each direction from the centre point.
We recommend starting with 1000 before trying larger areas.
chunky start
To check how far Chunky has got, run:
chunky progress
You should see information such as chunks processed, percentage complete, ETA and generation speed.
chunky pause
chunky continue
chunky cancel
For a modded server, a good first setup would be:
chunky world overworld
chunky center 0 0
chunky shape square
chunky radius 1000
chunky start
This will pre-generate a square area around 0 0 in the Overworld.
If you already have a main base location, use the base coordinates instead of 0 0.
You usually only need to pre-generate the Overworld first.
If players are also exploring the Nether or End and noticing lag there, you can generate those worlds too.
chunky world the_nether
chunky center 0 0
chunky radius 500
chunky start
chunky world the_end
chunky center 0 0
chunky radius 500
chunky start
We recommend using a smaller radius for the Nether and End unless you know you need a larger area.
For most servers, we suggest:
| World | Suggested radius |
|---|---|
| Overworld | 1000 |
| Nether | 500 |
| End | 500 |
For larger modded servers, you can increase this later, but it is best to start small and test first.
No. Chunky mainly helps with lag caused by new chunk generation.
It can help with:
It will not fix all types of lag.
Chunky may not help much with:
If your server still lags after pre-generating chunks, check whether the lag happens in one specific area, around certain machines, or only for certain players.
If you are unsure which version of Chunky to install or what radius to use, contact CLWHost support and we can point you in the right direction.