How to Use Spark Profiler on Minecraft Server

Spark is a profiler for Minecraft servers, proxies, and clients. For server owners, its biggest value is showing where tick time goes while lag is actually happening.

Modern Paper versions bundle Spark, and Paper's own profiling docs recommend profiling while the issue is active. On other platforms, install the Spark plugin or mod that matches your server software.

#Basic Capture

On a Paper server with Spark available, run:

/spark profiler start --timeout 600

That records for 10 minutes and returns a report link when it finishes. If you need a shorter manual capture:

/spark profiler start

Then stop it after the lag window:

/spark profiler stop

#What to Record With the Report

Save context beside the Spark link:

| Context | Example | | --- | --- | | Player count | 22 online | | Worlds active | survival, nether, resource | | Main symptom | block delay and mob freezes | | Hot locations | villager hall, gold farm, new chunks | | Recent changes | added quests plugin yesterday |

This prevents the report from becoming a mysterious link with no story.

#Reading the First Clues

Start with MSPT and the hottest paths. You are looking for patterns:

1. Entity ticking points toward mobs, villagers, item piles, or farms.
2. Chunk tasks point toward exploration, generation, IO, or forced chunks.
3. Plugin scheduler work points toward repeating plugin tasks.
4. Command execution points toward command blocks, datapacks, or scripted automation.
5. Garbage collection points toward memory pressure or heap sizing.

Use the report to choose the next guide. Entity-heavy profiles fit entity lag explained. Chunk-heavy profiles fit chunk lag explained. Plugin-heavy profiles fit how to find laggy plugins.

#After the Profile

Do not change five things at once. Pick the largest believable cause, make one controlled change, and profile again during the same workload.

Good next actions include:

1. Reconfiguring one noisy plugin.
2. Moving a farm out of spawn chunks.
3. Reducing simulation distance slightly.
4. Pregenerating a world border.
5. Limiting hopper or villager hotspots with player communication.

Spark is evidence, not a magic verdict. The best admin work is turning that evidence into a small reversible change.