Modded game servers have a bandwidth problem that vanilla servers never hit: every client that joins downloads the modpack. A 12 GB CurseForge or FTB pack multiplied by 40 players is close to half a terabyte of upload traffic every time the pack changes \u2014 and if your server pushes that traffic itself, players wait minutes to join and your tick loop competes with file transfer for I\/O. Caching the mod download outside the game process, and putting it behind a CDN or a separate web host, fixes both problems at once.<\/p>\n
When a modded server serves mod files directly, several things happen at once. Upload bandwidth that should be carrying player movement is consumed by file transfer. Disk I\/O that should be streaming chunks is consumed by reading mod archives off the same NVMe. And the game server process itself has to context-switch between ticking the world and serving HTTP. The result is the classic modded-server symptom: fine when empty, lagging the moment a wave of players joins after an update.<\/p>\n
Separating mod distribution from the game process removes all three conflicts. The game server keeps its CPU, RAM, and I\/O for ticking; mod delivery happens elsewhere.<\/p>\n
| Approach<\/th>\n | How it works<\/th>\n | Best for<\/th>\n<\/tr>\n<\/thead>\n |
|---|---|---|
| Server-served (default)<\/td>\n | Game server hosts mods directly<\/td>\n | Under 10 players, tiny packs<\/td>\n<\/tr>\n |
| Separate web\/cache host<\/td>\n | Nginx serving a static mod directory on another server or VPS<\/td>\n | Communities up to a few hundred players<\/td>\n<\/tr>\n |
| CDN in front<\/td>\n | Static mod files pushed to a CDN edge<\/td>\n | Large or geographically spread player bases<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n The middle option is the sweet spot for most communities: a cheap VPS or a second port on your dedicated box running Nginx with the mod directory mounted read-only. The CDN option adds global edge caching so a player in Europe pulls from a European edge instead of your single data center, cutting download time and removing the transit cost from your server entirely.<\/p>\n Bandwidth Math Before You Choose<\/h2>\nEstimate the traffic: pack size in GB \u00d7 average players per update \u00d7 number of updates per month. A 12 GB pack, 40 players, and four updates a month is roughly 1.9 TB of upload just for mods. If your host meters upload or caps transfer, that traffic competes directly with gameplay traffic and can push you into overage. Moving mod delivery to a CDN or an unmetered cache host often pays for itself in avoided overage alone.<\/p>\n Caching Configuration Essentials<\/h2>\nChoosing Between a Cache VPS and a Full CDN<\/h2>\nThe decision comes down to player geography and budget. If your community is concentrated in one region, a single cache VPS in that region is cheaper and simpler than a CDN: one Nginx config, one directory to rsync, no third-party account. If your players are spread across continents, a CDN’s edge network pays for itself by serving each player from a nearby point of presence, cutting both download time and the transit traffic that would otherwise cross expensive intercontinental links.<\/p>\n A middle path many communities use is a cache VPS for the primary region plus a CDN in front of that VPS. The VPS becomes the origin, the CDN caches the static mod files, and your game server never touches mod delivery at all. This keeps the origin cheap and still gets global edge coverage, and it means a single misconfigured player cannot hammer your game host’s uplink.<\/p>\n Security and Access Control for the Cache Host<\/h2>\n |