Administration Guide

Configuring Logging

CS/AIX writes log messages describing abnormal events (and, optionally, normal events) to log files. When you try to diagnose a problem, the first place to look is in the log files, because the log messages provide information about the cause of the problem and the action you should take.

CS/AIX logs messages for the following categories of event:

Problem

An abnormal event that degrades the system in a way perceptible to a user (such as abnormal termination of a session).

Exception

An abnormal event that degrades the system but that is not immediately perceptible to a user (such as a resource shortage), or an event that does not degrade the system but may indicate the cause of later exceptions or problems (such as receiving an unexpected message from the remote system).

Audit

A normal event (such as starting a session).

CS/AIX also maintains a usage log file, which is used to record information about the current and peak usage of CS/AIX resources.

To distinguish between logs relating to normal and error conditions, the different message categories are logged to different files. Problem and exception messages are logged to the error log file; audit messages are logged to the audit log file.

CS/AIX provides a backup mechanism to prevent log files from becoming too large and consuming disk resources. When a log file reaches the maximum permitted size, CS/AIX copies its current contents to a backup file and then clears the log file.

By default, CS/AIX uses the following log files:

Error log file

/var/sna/sna.err

/var/sna/bak.err (backup)

Audit log file

/var/sna/sna.aud

/var/sna/bak.aud (backup)

Usage log file

/var/sna/sna.usage

/var/sna/bak.usage (backup)

You can view the log files using a text editor or other AIX system utilities:

vi

View the file in a text editor. This allows you to move through the file forwards or backwards, and to search for particular entries.

pg

View a file one page at a time. This utility is simple and easy to use but useful only if the log file is small.

tail

View the tail (end) of a file. The end of the file is where the most recent log messages are. Use this utility with the -f option to monitor the log file while the system is running.

If you selected succinct rather than verbose logging, you can use the snahelp command to determine the cause and action information for a particular message number.

For most purposes, the default settings for logging are sufficient, but you can make the following types of changes:

• Indicate what categories of messages are to be logged.

  Problem messages are always logged and cannot be disabled. Logging is normally disabled for the other two message categories, but you can enable it if necessary.

• Specify the level of detail in logging messages.
• Change log file names and sizes.

To configure logging, use one of the following methods:

Motif administration program

Select Logging from the Diagnostics menu on the Node window.

Command-line administration program

Issue one of the following commands:

• set_global_log_type
• set_log_file

In addition to providing control over logging, the Motif administration program provides node-level control over tracing. The command-line interface provides greater control over both logging and tracing functions. For more information about logging and tracing, refer to Communications Server for AIX Diagnostics Guide.