WebLogic & JRockfit Flightrecording scheduling

WebLogic & JRockfit Flightrecording scheduling

Published on: Category: Oracle

As part of an analysis during a longer period of time, I wanted to investigate on a deeper level and for a longer period, JRockit JVM level.

Besides using WLDF embedded FlightRecording, it is also possible to separately record using jrcmd commandline. Within JRockit JDK you have this recording option you can use to take recordings for a certain period or a certain amount of time. These options are available in JRockit Command line (jrcmd.sh — a shell script shipped within your JDK installation directory).

The script collects a recording for an hour but you can set your time as you wish. Now, let’s see how the script is built up.

  • First, some parameters are set to identify which JVM you’d like to collect from.
  • Next, we define a period of time of how long recording should run, the actual jrcmd command and name of the compressed file.
  • We set some limits such as maxsize and compress to relieve your filesystem.
  • Last part of the script will take care of some cleaning up. All recorded files older than N days are removed, as well as the tmp folders on your managed server volumes! 

I used a remote JRockit MC Console, in which I can see the recordings. Usually you can download them if they have a green light, but because I cleaned the tmp dir of the managed server, I needed to copy the JFR’s manually and load them into my console.

I scheduled this script via crontab:

  1. 15 5-22 * * 1-5 nohup /u01/app/oracle/admin/general/wls/jrcmd.sh & >> /u01/app/oracle/admin/general/wls/jrcmdstart.log 2>&1 &

Using this approach we were able to get a day to day analysis on how applications were doing at JVM level, and we were able to solve our perfomanceproblem. The script was partly based on this article.

Publicatiedatum: 6 februari 2014

Michel Schildmeijer
About the author Michel Schildmeijer

Having made his start in the pharmacy sector, Michel transitioned to IT in 1996, working on a UNIX TTY terminal-based system and the MUMPS language. He currently works as a solutions architect at Qualogy, with a focus on middleware, application integration and service-oriented architecture. His passion for middleware started in 2000 when working as a support analyst for a financial institute with BEA WebLogic and Tuxedo. Michel is an expert on the WebLogic platform. He serves customers in his role as architect and advises them in all aspects of their IT landscape. He became an Oracle ACE in 2012 and wrote two books about WebLogic: Oracle WebLogic Server 11gR1 PS2: Administration Essentials and Oracle WebLogic Server 12c: First Look. He is a well-known speaker at national and international conferences and is recognised as an official Oracle Speaker. Read his blog: https://community.oracle.com/blogs/mnemonic

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