MustGather: 100% CPU usage on HP-UX
 Technote (troubleshooting)
 
Problem(Abstract)
MustGather for problems with IBM® WebSphere® Application Server 100% CPU usage on HP-UX. Gathering this information before calling IBM support helps familiarize you with the troubleshooting process and saves you time.

This list documents what is needed to begin troubleshooting a Java™ Virtual Machine (JVM™) that causes 100% CPU usage or an unusually high percentage on HP-UX.
 
Resolving the problem
If you have already contacted support, continue on to the component-specific MustGather information. Otherwise, click:
MustGather: Read first for all WebSphere Application Server products.

100% CPU usage specific MustGather information
Follow these instructions to set up the failing system for capturing required information:
  1. Install HP GlancePlus, if not already installed on system. Directions to install glanceplus:
    http://www.openview.hp.com/products/gplus/index.html.

    If you are using an older version of GlancePlus, it is recommended that you use the latest version.

  2. Enable verbosegc for the failing application server. This is necessary for debugging High CPU issues and does not have significant impact on performance.

  3. Clear all application server log files before starting test. You will have to stop the Application Server to delete all of the Application Server log files and then you can start the Application Server.

Determine the PID

To determine the PID of which process is consuming the highest CPU, you can perform the following:
  1. Use the top command
    • This command can provide a quick and easy way to identify high CPU processes. The process at the top of the list will be the one consuming the most CPU.
  2. Use the hpux_glance.sh script
    • You can have the hpux_glance.sh script output to a file to identify the Java PIDs that are consuming the most CPU.
    • Alternatively, using the -s argument will display the output to the terminal window. This still creates and appends an output file hpux_glance.out in the current directory.

      ./hpux_glance.sh -s

During the high CPU event, please follow the directions below:
  1. Run the following scripts in separate terminals when the Application Server process is experiencing the problem. These scripts will create output files in the current directory

    • ./hpux_glance.sh

      This command will run by default every 25 seconds for 13 intervals. GlancePlus must be installed on your system for this script to work. If the path cannot be found, you may manually enter a path to the glance executable using the -g argument. This script is attached below.

    • ./hpux_highcpu.sh PID

      This command requires the PID, which is the Process ID of the JVM that is causing high CPU. This script is also attached below.

  2. Collect the following files:
    • For V6.0 and V6.1 release:
      • Files in the <install_root>/profiles/<profile_name>/logs/
        <server_name>
        directory
      • FFDC logs from the <install_root>/profiles/<profile_name>/
        logs/ffdc
        directory
    • For V5.0 and V5.1 releases:
      • Files in the <install_root>/logs/server directory
      • FFDC logs from the <install_root>/logs directory
    • For all releases:
      • All of the *.out files created by the above commands
      • If the Web server is remote, send the http_plugin.log file from the Web server system.
  3. Follow instructions to send diagnostic information to IBM support.

    For a listing of all technotes, downloads, and educational materials specific to the 100% CPU Usage component, search the WebSphere Application Server support site.
 
Related information
Submitting information to IBM support
Steps to get support
MustGather: Readme first
Troubleshooting guide
Enabling verbose garbage collection (verbosegc)
 
hpux_glance.shhpux_highcpu.sh
 
Cross Reference information
Segment Product Component Platform Version Edition
Application Servers Runtimes for Java Technology Java SDK
 
 


Document Information


Product categories: Software > Application Servers > Distributed Application & Web Servers > WebSphere Application Server > 100% CPU Usage
Operating system(s): HP-UX
Software version: 6.1
Software edition:
Reference #: 1166017
IBM Group: Software Group
Modified date: Aug 19, 2008