1.3 Tips

Tips for Troubleshooting

Troubleshooting Guide

Common Problems for Data Collection

  • No core file produced ( Solaris )
    • Self-help
      Verify write permission in current working directory and core file
      Verify enough space for core file
      Verify ulimit -a shows "unlimited" for coredump
      Verify coreadm has per-process core dumps enabled
    • The coreadm output is incorrect
      Run coreadm(1M) and make the following recommended settings:
      #mkdir -p /var/cores
      #coreadm -g /var/cores/%f.%n.%p.core -e global -e process -e global-setid -e proc-setid -e log
      #coreadm
      global core file pattern: /var/cores/%f.%n.%p.core
      init core file pattern: core
      global core dumps: enabled
      per-process core dumps: enabled
      global setid core dumps: enabled
      per-process setid core dumps: enabled
      global core dump logging: enabled
    • Java specific 1 :
      The process received SIGSEGV or SIGILL but no core dump produced. May be the process handled it. For example, HotSpot VM uses the SIGSEGV signal for legitimate purposes such as throwing NullPointerException, deoptimization etc.
      Not all SIGSEGVs are bad! Only if the current instruction (PC) falls outside JVM generated code, the signal is unhandled by the JVM. Only in such cases, HotSpot dump core.
    • Java specific 2:
      The JNI Invocation API was used to create the VM. The standard Java launcher was not used. The custom Java launcher program handled the signal by just consuming it and produced the log entry silently.
      This has been seen with certain AppServers, WebServers. These JVM embedding programs transparently attempt to re-start (fail over) the system after abnormal termination.
      Not producing core is a feature and not a bug The above two are taken from section 3.2.3 in http://java.sun.com/j2se/1.5/pdf/jdk50_ts_guide.pdf
    • The coreadm output is correct but there is no core file generated when the application server or web server running in SSL mode crashed.
      For application server
      put the following statement "SSL_DUMP=1; export SSL_DUMP" in the startserv script of ( DAS or instance )
      For web server issue documentation http://sunsolve.central.sun.com/search/printfriendly.do?assetkey=1-9-63420-1 http://sunsolve.central.sun.com/search/printfriendly.do?assetkey=1-25-72079-1
    • Java thread dumps are not generated while performing "Ctrl and \ keys" are pressed, "kill -3" or "kill -QUIT" command.

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