WorldSlim

WorldSlim

Reduce Minecraft world file size by automatically cleaning chunks that players barely visit. Three layers of defense catch what vanilla autosave would otherwise commit to disk.

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What it does

Modern Minecraft (1.18+) keeps chunks loaded much longer than a player's view distance, and autosave writes them all to disk regardless of activity. WorldSlim hooks every layer of that pipeline:

1. ChunkCleaner — when a chunk does unload, intercept the save if `InhabitedTime` is low. 2. ChunkCleaner *(new in 2.0)* — every 2 seconds, pre-emptively clear the dirty flag on loaded low-`InhabitedTime` chunks so autosave skips them. 3. ChunkCleaner — periodically rewrite region files, removing chunks that slipped through the first two layers.

Player activity (placing blocks, attacking mobs, opening containers, picking up / dropping items) marks chunks as "force-save" so they survive cleanup.

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Highlights

- Async + bounded — unload + autosave + region rewrite. Aggressive without being unsafe. - Async + bounded — managed/force-save state stored in `plugins/WorldSlim/data/`, survives server restarts and Leaf/Moonrise's chunk-PDC strip. Crash-safe (lost marks degrade to "leave it alone"). - Async + bounded *(`cleanup.aggressive: true`)* — restores the pre-1.0.6 cleanup logic, achieves 90%+ cleanup rate on fresh servers. Off by default to protect builds on established worlds. - Async + bounded — `/worldslim diagnose` for runtime counters, `/worldslim scan` for raw-NBT inspection of any region file, `/worldslim chunk` for full decision-tree of the chunk you're standing in. - Async + bounded at `plugins/WorldSlim/logs/`, configurable level. - Async + bounded *(new in 2.0.1)* — new fields auto-injected on upgrade, preserving your edits and comments. - Async + bounded — every disk operation runs off the main thread, with a 5-second timeout that safely skips when the server is busy.

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Compatibility

| Server | PDC Persistence | Registry | AutosaveShield | |--------|-----------------|----------|----------------| | Paper 1.21.x | Yes | Yes | Yes | | Purpur 1.21.x | Yes | Yes | Yes | | Folia 1.21.x | Yes | Yes | Partial | | Leaves 1.21.x | Yes | Yes | Yes | | Leaf 1.21.x | Stripped | Load-bearing | Limited |

Requires Minecraft 1.21.x and Java 21.

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Commands

| Command | Description | |---------|-------------| | `/worldslim status` | Show plugin status and active configuration | | `/worldslim stats` | Total chunks scanned/cleaned and space saved | | `/worldslim chunk` | Full decision tree for the chunk you're standing in | | `/worldslim cleanup` | Run a cleanup pass immediately | | `/worldslim diagnose [here]` | Runtime diagnostic snapshot. Append `here` for current-chunk details | | `/worldslim scan` | Parse the current region file's raw NBT and report what tags survived | | `/worldslim reload` | Reload `config.yml` (also runs config migration) | | `/worldslim reset` | Reset cleanup statistics |

Aliased to `/ws`. Permission: `worldslim.admin` for mutating commands; `worldslim.use` for the read-only ones.

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Quick start

1. Drop the jar in `plugins/`, restart. 2. Default config is conservative (preserves any chunks that look pre-existing). Works without configuration on most servers. 3. On an established server with builds — set `cleanup.aggressive: true` for the best cleanup rate. 4. On an established server with builds — leave `aggressive: false` (default) and let the registry track new chunks going forward.

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Configuration highlights

```yaml

Chunk lifetime threshold. Below this, chunks may be cleaned.

Default 1200 ticks = 60 seconds.

min-inhabited-time: 1200

cleanup: interval-minutes: 30 run-on-startup: false

Pre-1.0.6 cleanup behavior. Highly recommended for fresh servers.

aggressive: false

autosave-shield: enabled: true interval-ticks: 40 # 2s

logging: file-enabled: true level: INFO # DEBUG / INFO / WARN / ERROR

worlds: enabled: [] # if non-empty, ONLY these worlds are managed disabled: [] # always-skipped worlds ```

Full default config (with all comments) is generated on first run.

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Reporting issues

Please include: - `/worldslim diagnose` screenshot - Latest log from `plugins/WorldSlim/logs/` - Server type and version