Introduction / FirstSpirit Server control / Java Flight Recorder

Java Flight Recorder (JFR)

The Java Flight Recorder (JFR) enables monitoring and diagnosing Java applications. It is included in the Oracle JDK.

As of Java 11, the JFR can be used to retrieve additional information (https://access.redhat.com/documentation/en-us/openjdk/17/html-single/using_jdk_flight_recorder_with_openjdk/index).

The installation and update archives contain a default configuration for the JFR as of FirstSpirit 2021-06.

By default, the JFR is deactivated. To activate it, the

fs-recording.conf.disabled

file in the conf directory must be renamed to

fs-recording.conf

The default configuration in this file is as follows:

#encoding=UTF-8
-XX:FlightRecorderOptions=repository=work/recording
-XX:StartFlightRecording=name=FirstSpirit,disk=true,dumponexit=true,
   filename=log/fs-recording.jfr,maxsize=50m,maxage=1d

In the JDK Mission Control, the relevant JFR information can thereby be retrieved under “FirstSpirit”.

In case of an unexpected shut-down of the server, a dump will be created and stored in the fs-recording.jfr file (directory log). It is configured for a maximum size of 50 Mb and a maximum age of one day.

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