Tired of Bloated World Saves?
Minecraft saves far more world data than most players ever interact with. Over time, that can turn backups, transfers, and long-term world storage into a much bigger problem than it needs to be.
Chunkis tackles that at the storage layer.
What Does It Do?
Chunkis replaces vanilla chunk persistence with a custom CIS format focused on safer save/load behavior, migration control, and smaller world storage in many real worlds.
Instead of relying entirely on vanilla's full chunk save format, Chunkis stores chunk data in its own format and reconstructs what it needs on load.
The result: world storage can be significantly smaller than vanilla, with no gameplay changes and no FPS or TPS boost claims.
Why It Matters
| Smaller world storage | Often substantially smaller than vanilla saves |
| Safer persistence | 3.0.0 focuses heavily on save/load correctness and migration safety |
| Faster backups and transfers | Smaller worlds are easier to move, upload, and archive |
| Custom persistence layer | Chunkis controls chunk storage instead of depending on vanilla Anvil behavior |
⚠️ Beta Notice ⚠️
Chunkis is currently in Beta. It fundamentally changes how your world data is stored, so treat it accordingly:
- Always keep a backup before installing or updating
- Test on a new world or a copy first, not your main save
1.21.11versions3.0.0+currently have a known storage regression compared to older Chunkis releases, even though stability and correctness have improved
Development Notice
Development will be slower until late June due to school and other responsibilities.
The current plan is:
- continue improving compression and storage efficiency after June
- keep improving stability and persistence behavior
- continue work on future
1.21.11+versions once that version line is stable enough to move forward cleanly
I do plan to continue the project. This is a pause in pace, not the end of development.
Found a Bug?
If something goes wrong, please open an issue.
If you want to contact me directly, my Discord is: Liparakis
FAQ
Will this improve my FPS?
No. Chunkis is a storage and persistence optimization. Rendering and gameplay performance are unaffected.
Is Chunkis always smaller than vanilla?
No. In many worlds it is still smaller, sometimes substantially smaller, but it does not guarantee a storage win in every world.
Will older Minecraft versions be supported?
Development focuses on the latest release. Older versions will not receive regular updates unless a critical bug is reported. If anyone wants to backport changes, they are welcome to open a pull request.
Can I use this with my existing world?
Yes. Chunks convert to CIS format as they save.
Can I revert to Anvil format?
Not automatically. Restore from a backup made before Chunkis was installed.
Fabric 1.21+