What are Aikar's Flags for Minecraft?

Aikar's Flags are a set of JVM (Java Virtual Machine) startup arguments optimized specifically for Minecraft servers. They configure the garbage collector (G1GC) to minimize lag spikes and improve overall performance. They are the community-recommended standard for Paper and Spigot servers.

How much RAM should I allocate to my Minecraft server?

For a small server (1-10 players), 2-4 GB is sufficient. For medium servers (10-50 players), 4-8 GB is recommended. Large servers with many players or heavy plugins may need 8-16 GB or more. Do not allocate more than 70-80% of your total system RAM.

How do I use the generated startup script?

Copy the generated script, save it as start.sh (Linux/Mac) or start.bat (Windows) in the same directory as your server JAR file. Make it executable (chmod +x start.sh on Linux) and run it to start your server with the optimized flags.

What is the difference between Aikar's Flags and MeowIce's Flags?

Aikar's Flags use the G1GC garbage collector and are battle-tested on large production servers. MeowIce's Flags use the ZGC garbage collector which is better for very large heap sizes (12+ GB) but may perform differently on smaller allocations. Most servers should use Aikar's Flags.

Minecraft Flags Generator

Generate optimized startup scripts for your Minecraft server

Configuration

Operating System

Server Software

Flag Preset Recommended by PaperMC for most servers

RAM Allocation

1 GB 4 GB 32 GB

Allocate at least 4GB for optimal performance. Don't allocate more than your system has!

Server JAR Filename

Additional Options

No GUI (--nogui) Auto-restart on crash Use environment variables

Startup Script

About These Flag Presets

Aikar's Flags

The most widely recommended flags for Minecraft servers. Optimized for G1GC garbage collection to reduce lag spikes and improve overall performance. Officially recommended by PaperMC.

Aikar's Flags (12GB+)

Modified version of Aikar's flags with larger G1 region sizes for servers with 12GB or more RAM. Provides better performance for large servers with many players.

MeowIce's Flags

Optimized for GraalVM with ZGC garbage collection. Best for modern servers with high player counts. Combines Aikar's optimizations with additional JVM features for smoother performance.

hilltty's Flags

Alternative optimization flags focused on reducing memory overhead and improving startup times. Good for servers with limited resources.

Velocity Flags

Specifically optimized for Velocity proxy servers. Uses different GC settings appropriate for proxy workloads which differ from game servers.

No Flags

Basic startup without optimization flags. Use this if you want to add your own custom JVM arguments or for debugging purposes.