How to run Java Flight Recorder on a Minecraft server

Type jfr start in the server console, let the lag happen, then jfr stop. A .jfr file is saved in the debug folder for JDK Mission Control.

jfr

Starts or stops a Java Flight Recorder profile for deep analysis of server performance.

/jfr <start|stop>

Examples

jfr start

From the console, starts recording.

jfr stop

Stops and saves the recording.

Arguments

start|stopRequired: Begin or end the recording.

What it does

Records detailed JVM and game events until you run jfr stop, then writes a .jfr file to the server's debug folder. Open it with JDK Mission Control or a similar tool.

Good to know

Needs operator permission level 4 (owner), the level op grants by default.
Recording adds a little overhead, so do not leave it running.

Run it on your server

On a SLASHPLAY server, type it in the Console tab without the leading slash; in game, operators type it in chat with the slash. New to this? Start a Minecraft server first.

Your own
Minecraft server.

Start a Minecraft server All commands

From $0.03 an hour, only while it runs. New accounts get 6 free tokens.