01 What Chunky can improve
Chunky schedules chunk pregeneration so the server can create terrain before players explore it. It can reduce the amount of new-world generation during a later session; it does not fix every kind of lag. A base full of active entities or expensive plugin tasks can still be slow inside already-generated terrain.
Choose the release for the actual server platform and game version. Record the seed, world generator and intended dimensions first. Pregenerating with the wrong generator creates persistent terrain that changing a plugin later will not simply erase. Back up an established world before starting a substantial generation task.
02 Select a small area explicitly
The project command reference ↗ uses radius in blocks. This example selects a circle of radius 1000 around 0,0 in a world literally named world. Replace that name with your own. In a server console, commands normally omit the leading slash.
/chunky world world
/chunky shape circle
/chunky center 0 0
/chunky radius 1000
/chunky selection
/chunky startInspect the selection before starting. A radius of 1000 is not a diameter of 1000. Doubling a circular radius roughly quadruples its area: πr² changes by a factor of four. Chunk boundaries and already-generated terrain affect the actual work, so use that geometry for planning rather than claiming a fixed disk size or completion time.
03 Monitor the machine while the task runs
Start during a quiet play window. Observe free disk space, memory pressure, responsiveness and the task’s progress. Use /chunky progress to inspect it; if normal play becomes difficult, use /chunky pause. The documented /chunky continue resumes a saved task.
Give each dimension its own deliberate selection and test. Do not assume the overworld’s area, scale or generation cost should be copied to every dimension. On rented hosting, confirm that sustained pregeneration fits the plan’s workload limits instead of assuming an “unlimited” label permits any job. If disk space becomes tight, pause before attempting a cleanup.
04 Cancel does not delete the generated world
The project distinguishes cancellation from trimming. /chunky cancel discards task progress but leaves chunks already generated. Trimming deletes chunks and requires a separate recovery decision; it is not a routine “undo pregeneration” button. Do not run a copied trim command against the only world.
After generation, restart normally if your workflow requires it, visit samples near the center and boundary, and verify that the intended generator was used. Then compare a later exploration session under similar conditions. If lag remains in an established area, use spark rather than expanding the pregenerated radius again. For deliberate offline pruning, read the MCA Selector backup workflow.