How to Host a Fantasy MC Server (Fabric 1.21.1 Setup Guide)

Start with at least 6 GB of RAM allocated. That's the recommended floor for Fantasy MC's own catalog listing — the pack stacks magic systems, fantasy biome generation, dungeon content, and RPG elements on top of Sodium and Iris, and going below that floor shows up as biome generation stutter and dungeon chunk lag rather than an outright crash.

Import the modpack through a proper modpack installer rather than copying a client export onto the server. A clean import pulls the correct Fabric loader build for 1.21.1 and the matching server-side mod set, so you're not stuck guessing which client-only mods to strip out by hand.

Watch the server logs through the full first boot. Fantasy MC's magic systems and dungeon generation do real work on startup — let it finish loading world data and registering content before assuming it's ready, and check for any mod load errors in the log rather than just waiting for the console to go quiet.

Only invite players once that first boot has completed cleanly with no errors. Letting people join mid-boot on a magic-and-dungeon pack like this is a common way to end up with corrupted chunk data in freshly generated fantasy biomes.

Take a backup before importing a world, updating the Fabric loader, or changing any mod configs. Fantasy MC worlds carry progress in enchanted structures, dungeon clears, and RPG stat progression — losing that to a bad update is the kind of mistake you only make once.