Worlds grow quietly. One player flying to find a biome can add a gigabyte in an evening, and none of it ever shrinks on its own.
Why it happens
Almost all of a world's size is in world/region, the .mca files that hold terrain. Each one covers 32×32 chunks and gets written the moment a player loads that area — even if they flew straight over it and never came back. Deleting builds does not shrink them, because the chunk still exists; it is just emptier.
What actually takes the space
| What | Roughly |
|---|---|
| Region files | Almost everything. Grows with explored area, not with what is built. |
playerdata | Small. A few kilobytes per player. |
| Plugin data and databases | Usually small, but a logging plugin left running for a year is not. |
| Backups stored on the server | Sometimes larger than the world itself. Check this first. |
Reclaiming space, in order of payoff
- Delete old backups that live on the server
The single most common cause of a full disk. Download the ones worth keeping and remove the rest.
- Trim unused chunks
A world-trimming tool removes region files nobody has visited in a long time. It is the only thing that genuinely shrinks a world, and it needs a backup first.
- Set a world border
It does not shrink anything today, but it stops the growth from continuing.
Removing an .mca file that a player's base sits in deletes that base. Trimming tools exist because picking files by name is guesswork, and the guess is destructive.
A pre-generated world inside a border has a known final size. It is bigger on day one, and it stops surprising you afterwards.