Log streams and expected output

Investigating the logging and tracing output for the application server is an excellent way to observe performance, diagnose problems, and gain a general understanding of how the application server is working within your environment. The expected output locations for logging and trace information can be different depending on the operating system on which the application server is running.

Note: This topic references one or more of the application server log files. As a recommended alternative, you can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM® i systems. You can also use HPEL in conjunction with your native z/OS® logging facilities. If you are using HPEL, you can access all of your log and trace information using the LogViewer command-line tool from your server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.
[IBM i][AIX Solaris HP-UX Linux Windows]
Table 1. Log and trace output for distributed and IBM i. This table lists the expected output for logging and tracing output streams for distributed and IBM i operating systems
Log or trace stream Expected output - basic log and trace mode Expected output - HPEL log and trace mode
Java™ trace Trace.log. You must have tracing enabled.
  • HPEL trace repository.
  • HPEL TextLog*.log, when you enable this log.
Java logs
  • Trace.log, when you enable tracing.
  • Activity.log. The Activity.log file is also directed to the Showlog output.
  • SystemOut.log
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log.
System.out stream
  • Trace.log
  • SystemOut.log
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log.
System.err stream SystemErr.log
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log
cout (the C or C++ output stream) Native stdout Native stdout
cerr (the C or C++ error stream) Native stderr Native stderr
Figure 1. Distributed and IBM i - Basic log and trace mode. Distributed and IBM i - Basic log and trace mode
Graphical representation of logging on distributed and IBM i
Figure 2. Distributed and IBM i - HPEL log and trace mode. Distributed and IBM i - HPEL log and trace mode
Graphical representation of HPEL log and trace on distributed and IBM i
[z/OS]
Table 2. Log and trace output for z/OS. This table lists the expected output for logging and tracing output streams when the application server is installed on z/OS.
Log or trace stream Expected output - traditional log and trace mode Expected output - HPEL log and trace mode
Java trace SYSPRINT
Avoid trouble: Trace information, which includes events at the Fine, Finer and Finest levels, is written only to this output. If you do not enable diagnostic trace, setting the log detail level to Fine, Finer, or Finest does not affect the logged data.
  • HPEL trace repository
  • HPEL TextLog*.log, when you enable this log
Java logs (Audit level) Transformed into write-to-operator (WTO) output to the hard copy logging stream Same outputs as traditional log and trace mode, plus the following:
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log
Java logs (other levels) SYSOUT or your configured error stream Same outputs as traditional log and trace mod, plus the following:
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log
System.out SYSPRINT
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log
System.err SYSOUT
  • HPEL log repository
  • HPEL TextLog*.log, when you enable this log
cout (the C or C++ output stream) SYSPRINT SYSPRINT
cerr (the C or C++ error stream) SYSOUT SYSOUT
Native trace SYSPRINT
Avoid trouble: Trace information, which includes events at the Fine, Finer and Finest levels, is written only to this output. If you do not enable diagnostic trace, setting the log detail level to Fine, Finer, or Finest does not affect the logged data.
SYSPRINT
Avoid trouble: Trace information, which includes events at the Fine, Finer and Finest levels, is written only to this output. If you do not enable diagnostic trace, setting the log detail level to Fine, Finer, or Finest does not affect the logged data.
Native Message logs SYSOUT or your configured error stream SYSOUT or your configured error stream
Note: This topic references one or more of the application server log files. As a recommended alternative, you can configure the server to use the High Performance Extensible Logging (HPEL) log and trace infrastructure instead of using SystemOut.log , SystemErr.log, trace.log, and activity.log files on distributed and IBM i systems. You can also use HPEL in conjunction with your native z/OS logging facilities. If you are using HPEL, you can access all of your log and trace information using the LogViewer command-line tool from your server profile bin directory. See the information about using HPEL to troubleshoot applications for more information on using HPEL.
When considering the direction of log and trace streams, keep in mind the following acronyms and abbreviations:
cerr
C or C++ error steam
cout
C or C++ output steam
DD
Data Description statements
HFS
Hierarchical File System
JCL
Job Control Language
JES
Job Entry Subsystem
MVS™
Multiple Virtual Storage
WTO
Write-to-operator
WTOR
Write-to-operator with reply
Figure 3. z/OS - Traditional log and trace mode. z/OS - Traditional log and trace mode
Graphical representation of traditional logging on z/OS
Figure 4. z/OS - HPEL log and trace mode. z/OS - HPEL log and trace mode
Graphical representation of HPEL logging on z/OS