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Chunkis

Chunkis is a Minecraft Fabric mod that replaces vanilla chunk persistence with a Chunkis-managed storage pipeline.

It provides:

• CIS-based chunk storage
• Runtime mutation tracking
• Snapshot-based persistence
• Chunk restoration during world loading
• Client-side chunk delta synchronization
• CIS format migration
• Vanilla MCA → CIS world migration
• Storage inspection and debugging tools

Project Status

Chunkis is actively developed for Minecraft 1.21.11 using Java 21 and Fabric.

The project is currently focused on:

• Stabilizing the CIS storage engine
• Ensuring reliable save and load behavior
• Preserving chunk metadata and entities
• Improving MCA → CIS migration
• Validating durability through automated tests and game tests

Architecture

Chunkis is divided into four primary modules:

• common — Shared models, codecs, compression, and debug structures
• storage — CIS storage engine, region files, mappings, and inspection tools
• migration — CIS version migrations and storage rewrites
• fabric — Minecraft integration, mixins, tracking, restoration, networking, and runtime migration

Start with System Overview for the high-level execution flow.

Documentation

• Architecture
• Developer Guide
• Storage Format
• Save Pipeline
• Load and Restore Pipeline
• Delta and Ownership Model
• Migration and Versioning
• Debugging
• CIS Format Specification

Development

Build and test Chunkis with:

./gradlew build
./gradlew test
./gradlew runGameTest