Free Server Saver

# Free Server Saver **Lag reducer for low-RAM Minecraft servers (Falixnodes, Minehut, self-hosted), anything stuck on 2-4 GB of RAM.** If you've ever seen any of this on your server, it's the same root cause: - 🟦 Mobs teleporting 5–10 blocks instead of moving smoothly - 🟦 You and a friend get disconnected even though only 2 people are online - 🟦 The server freezes for half a second every few minutes - 🟦 `Server crashed because it ran out of memory` after a fine hour of play - 🟦 `OutOfMemoryError: Metaspace` even though RAM Boost is active All of those are **garbage collection pauses**. Your host gives you a small heap, modpacks fill it, the JVM stops the world to clean up, and to players that looks identical to network lag. **Free Server Saver polls heap pressure every 2 seconds and gradually scales back AI ticks, mob spawns, view distance, and chunk loads _before_ the heap fills.** No GC pause, no rubber-banding, no disconnects. ## How it works Five tiers. Static thresholds, hysteresis on recovery: | Heap | Tier | What changes | |---|---|---| | < 60% | NORMAL | Vanilla behavior | | 60–70% | L1 | Far mobs tick every other tick; 50% of natural spawns rejected | | 70–80% | L2 | Distant mobs at 1/8 tick rate; all natural spawns rejected | | 80–85% | L3 | View distance compressed to 6 chunks | | ≥ 85% | L4 EMERGENCY | Distant mobs force-discarded; server tick rate halved | When the heap recovers, every change reverses automatically. ## Protections — what stays normal even at L4 - **Bosses** (EnderDragon, Wither, Warden, Elder Guardian, Ravager, Hoglin, or anything with > 80 max HP) - **Villagers, wandering traders, golems, allays** — your iron farm and trading hall keep working - **Named, leashed, tamed, persistent** mobs - **Combat-engaged mobs** (`getTarget() != null`) — keep ticking at full rate - **Newly spawned (< 10 s)** mobs — grace period - **Crops, leaves, snow, fire** — random ticks are NEVER touched (Lithium handles those better) ## Also addresses - **4 GB world cap** — `/fss storage` and `/fss prune` for the host's hard ceiling - **10-minute startup limit** — boot-time history + early warning if you're approaching it - **Metaspace OOM** — RAM Boost extends heap, not Metaspace. We watch Metaspace separately and warn before the crash - **Chunk-generation lag** — `/fss pregen <radius>` for spawn-area pre-gen (yields to Chunky if installed) - **Mob-farm detection** — opt-in scan that flags chunks with 30+ same-type mobs - **Stuck-entity crashes** — entities / block-entities that throw the same tick exception repeatedly are auto-quarantined before they crash an unattended server (yields entirely to Neruina / Bug Fix Mod / Failsafe if one is installed; bosses are never discarded) ## Plays well with everything **Free Server Saver detects competing mods and yields** rather than fighting them. Install side-by-side with any of: - Lithium / FerriteCore / ModernFix — these handle static optimization; we handle adaptive throttle - Adaptive Performance Tweaks / Tick Dynamic / Tick Tweaks — we yield to their tick-time logic - Where's my Brain / DAB / OptimizeMod / Immersive Optimization / No See No Tick — we yield to their distance throttle - Chunky — we yield our pregen command to its better one The startup log shows which modules yielded and why. No double-throttling, no `/tick rate` fights, no surprises. ## Commands (`/fss`, server-op only) The short form is `/fss`; `/freeserversaver` works too as the full alias. | Command | What it shows | |---|---| | `help` | All subcommands with descriptions | | `status` | Current tier + heap percentage | | `metrics` | Heap, tier, players, chunks, view distance | | `history` | Last 20 tier transitions, color-coded | | `env` | JVM heap/CPU snapshot from server start, with RAM Boost detection | | `lagspikes` | Recent 100ms+ ticks with heap state at the time | | `top entities` | Top-10 entity types by count | | `inspect chunks` | Per-dimension loaded / forced / player counts | | `tuning` | Current AutoTuner threshold offset | | `prune` | Identify unreachable loaded chunks (flood-fill) | | `storage` | World directory size vs the host's 4 GB cap | | `pregen <radius>` | Pre-generate chunks around you | | `quarantine` | Recently quarantined entities / block-entities | ## Languages Output translated to **9 languages** — English, 日本語, Deutsch, Português (BR), Español, 简体中文, 한국어, Français, Русский. A Japanese client sees Japanese on a server in any locale. The translations are machine-generated as a starting point. Native-speaker corrections are very welcome — open a PR or issue. ## What it does NOT do - ❌ Network ping issues — that's geographical, no mod can help - ❌ Bypass the host's idle-shutdown timer with fake players — that's exactly what many free hosts ban (Carpet). Free Server Saver works within the host's rules ## Requirements - Minecraft 1.21.1 - NeoForge - JDK 21 (1.21.2+ port pending — vanilla's random tick logic changed in 1.21.2 and we