# WorldSlim<\/p>\n
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.<\/p>\n
—<\/p>\n
## What it does<\/p>\n
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:<\/p>\n
1. **ChunkUnloadListener** \u2014 when a chunk does unload, intercept the save if `InhabitedTime` is low.
\n2. **AutosaveShield** *(new in 2.0)* \u2014 every 2 seconds, pre-emptively clear the dirty flag on loaded low-`InhabitedTime` chunks so autosave skips them.
\n3. **ChunkCleaner** \u2014 periodically rewrite region files, removing chunks that slipped through the first two layers.<\/p>\n
Player activity (placing blocks, attacking mobs, opening containers, picking up \/ dropping items) marks chunks as “force-save” so they survive cleanup.<\/p>\n
—<\/p>\n
## Highlights<\/p>\n
– **Three-layer architecture** \u2014 unload + autosave + region rewrite. Aggressive without being unsafe.
\n– **File-based ChunkRegistry** \u2014 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”).
\n– **Aggressive mode** *(`cleanup.aggressive: true`)* \u2014 restores the pre-1.0.6 cleanup logic, achieves 90%+ cleanup rate on fresh servers. Off by default to protect builds on established worlds.
\n– **Diagnostics** \u2014 `\/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.
\n– **Daily-rotating file logger** at `plugins\/WorldSlim\/logs\/`, configurable level.
\n– **Config migration** *(new in 2.0.1)* \u2014 new fields auto-injected on upgrade, preserving your edits and comments.
\n– **Async + bounded** \u2014 every disk operation runs off the main thread, with a 5-second timeout that safely skips when the server is busy.<\/p>\n
—<\/p>\n
## Compatibility<\/p>\n
| Server | PDC Persistence | Registry | AutosaveShield |
\n|——–|—————–|———-|—————-|
\n| Paper 1.21.x | Yes | Yes | Yes |
\n| Purpur 1.21.x | Yes | Yes | Yes |
\n| Folia 1.21.x | Yes | Yes | Partial |
\n| Leaves 1.21.x | Yes | Yes | Yes |
\n| Leaf 1.21.x | Stripped | **Load-bearing** | Limited |<\/p>\n
Requires Minecraft 1.21.x and Java 21.<\/p>\n
—<\/p>\n
## Commands<\/p>\n
| Command | Description |
\n|———|————-|
\n| `\/worldslim status` | Show plugin status and active configuration |
\n| `\/worldslim stats` | Total chunks scanned\/cleaned and space saved |
\n| `\/worldslim chunk` | Full decision tree for the chunk you’re standing in |
\n| `\/worldslim cleanup` | Run a cleanup pass immediately |
\n| `\/worldslim diagnose [here]` | Runtime diagnostic snapshot. Append `here` for current-chunk details |
\n| `\/worldslim scan` | Parse the current region file’s raw NBT and report what tags survived |
\n| `\/worldslim reload` | Reload `config.yml` (also runs config migration) |
\n| `\/worldslim reset` | Reset cleanup statistics |<\/p>\n
Aliased to `\/ws`. Permission: `worldslim.admin` for mutating commands; `worldslim.use` for the read-only ones.<\/p>\n
—<\/p>\n
## Quick start<\/p>\n
1. Drop the jar in `plugins\/`, restart.
\n2. Default config is conservative (preserves any chunks that look pre-existing). Works without configuration on most servers.
\n3. **On a fresh server** \u2014 set `cleanup.aggressive: true` for the best cleanup rate.
\n4. **On an established server with builds** \u2014 leave `aggressive: false` (default) and let the registry track new chunks going forward.<\/p>\n
—<\/p>\n
## Configuration highlights<\/p>\n
“`yaml
\n# Chunk lifetime threshold. Below this, chunks may be cleaned.
\n# Default 1200 ticks = 60 seconds.
\nmin-inhabited-time: 1200<\/p>\n
cleanup:
\n interval-minutes: 30
\n run-on-startup: false
\n # Pre-1.0.6 cleanup behavior. Highly recommended for fresh servers.
\n aggressive: false<\/p>\n
autosave-shield:
\n enabled: true
\n interval-ticks: 40 # 2s<\/p>\n
logging:
\n file-enabled: true
\n level: INFO # DEBUG \/ INFO \/ WARN \/ ERROR<\/p>\n
worlds:
\n enabled: [] # if non-empty, ONLY these worlds are managed
\n disabled: [] # always-skipped worlds
\n“`<\/p>\n
Full default config (with all comments) is generated on first run.<\/p>\n
—<\/p>\n
## Reporting issues<\/p>\n
Please include:
\n– `\/worldslim diagnose` screenshot
\n– Latest log from `plugins\/WorldSlim\/logs\/`
\n– Server type and version<\/p>\n","protected":false},"excerpt":{"rendered":"
A lightweight chunk save optimization plugin for Paper servers. WorldSlim reduces your world file size by automatically cleaning up chunks that players have barely visited.<\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"_minecraft_slug":"worldslim","_minecraft_project_id":"7cyR8p4W","_minecraft_author":"babyxxi","_minecraft_license":"LicenseRef-All-Rights-Reserved","_minecraft_downloads":38,"_minecraft_follows":0,"_minecraft_client_side":"unsupported","_minecraft_server_side":"required","_minecraft_storage_type":"zip","_minecraft_archive_name":"worldslim.zip","_minecraft_size_bytes":336527,"_minecraft_version_count":9,"_minecraft_updated_at":"2026-05-15T21:38:40.769705Z","_minecraft_date_created":"2026-03-03T21:20:08.839736Z","_minecraft_date_modified":"2026-04-29T07:13:33.866538Z","_minecraft_project_url":"https:\/\/modrinth.com\/mod\/worldslim","_minecraft_icon_attachment_id":0,"_minecraft_imported_at":"2026-06-09T21:33:18+00:00","_minecraft_import_hash":"730880d603a07c681b8a39cf59408ab7","_minecraft_versions":"","_minecraft_links":"","_minecraft_gallery":"","_minecraft_api_metadata":""},"mod_category":[125,126,90,127,128,91,92],"mod_loader":[131,132,133],"minecraft_version":[62,37,40,41,73,74,38,78,79,80,81,82],"class_list":["post-171630","mod","type-mod","status-publish","hentry","mod_category-folia","mod_category-management","mod_category-optimization","mod_category-paper","mod_category-purpur","mod_category-storage","mod_category-utility","mod_loader-folia","mod_loader-paper","mod_loader-purpur","minecraft_version-1-21","minecraft_version-1-21-1","minecraft_version-1-21-10","minecraft_version-1-21-11","minecraft_version-1-21-2","minecraft_version-1-21-3","minecraft_version-1-21-4","minecraft_version-1-21-5","minecraft_version-1-21-6","minecraft_version-1-21-7","minecraft_version-1-21-8","minecraft_version-1-21-9"],"yoast_head":"\n