breif descriptions of websphere logs

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Copyright (c) by Foxit Software Company, 2004 - 2007
For Evaluation Only.
WebSphere Environment Log Management
In a websphere environment, there will be multiple log files for your application servers, http servers
etc. If we do not have rotation or automation in place, these logs can grow in large size and occupy more
space and in some cases may create disturb the normal operations as well.
Recently, someone mailed me about IBM http server failing to start without writing anything to log files;
they also mentioned that they have enough space on the disk for the log files to write. I suggested them
to change the logging a higher detail levels and see if anything shows up in the logs. Finally, the issue is
with the http_plugin.log file which has grown beyond 2GB [max file limit, on their machine]. Until the
issue is resolved, the web server is down. Another important point is that, the log file size will impact the
performance of your servers, as the larger files take more system resources. Similar things can happen
with your websphere application server as well. So, how can we avoid such situations?
The solution is log management or in simple terms, regular maintenance on log files. As a part of this log
management, you will be rotating the log files and archive the older logs. Before start implementing the
log management, we need to have the list of log files to manage and a policy to manage them.
Server Log file name Options
Websphere SystemOut.log In-built feature to rotate logs based on
application server & SystemErr.log size and time
Trace.log In-built feature to rotate logs based on
size
Activity.log No in-built feature
IBM http server Access.log & In-built feature to rotate logs based on
error.log size and time
Websphere plug-in Plug-in log No in-built feature
In websphere application server, for native logs, core files and service log there is no in-built feature for
rotating log files. In Http server, there is no option to rotate the plug-in log file. If in-built options are not
available to rotate a log, we are going to implement it using scripts and other OS level features.
Now you’ve list of the log files, which needs maintenance. So its time to prepare a strategy for their
maintenance. This is simply answering 2 questions.
1. When do you want to rotate log files [size or time]
2. How many log files you want to keep

2. Edited by Foxit PDF Editor
Copyright (c) by Foxit Software Company, 2004 - 2007
For Evaluation Only.
A. WebSphere Application Server
A.1 JVM logs [SystemOut and SystemErr]
You can set the log rotation options for these files from the administration console. Navigate to
Troubleshooting logs and trace server name jvm logs .
Choose file size or time under log file rotation option and save the changes. The log files are rotated
automatically based on your option. The old log file will be named as SystemOut_yy.mm.dd_hh.mm.ss.log /
SystemErr_yy.mm.dd_hh.mm.ss.log. You can also specify how many old log files you want to retain.
In the above example [screenshot], logs will be rotated when they reach 50MB and 50 old logs will be
retailed.

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A.2 Trace Log
If you enabled the tracing, the trace log can be rotated based upon its size. Also you can mention the
maximum number of historical files.
A.3 Service Log
This is the service log otherwise known as activity log which can be read using log analyzer tool, to
display events to analyze problems based on symptom database. You have an option to specify the
maximum file size but it will not be rotated when it reaches the maximum defined size. When the max
size is reached, it wraps in place.

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Copyright (c) by Foxit Software Company, 2004 - 2007
For Evaluation Only.
B. IBM http server [access.log and error.log]
To implement the rotation of the log files for IBM http server, you can use the rotatelogs utility which
can be found under bin directory of your http server installation. Using this, you can rotate the log files
based on size, time. Check here for more details. Using the piped logging option, we can directly use
rotatelogs utility in our virtualhosts definitions. Here is an example of entries for this implementation.
<virtualhost>
…
# Rotates access log every 24 hours.
CustomLog "|/usr/IBM/httpserver/bin/rotatelogs /usr/IBM/httpserver/logs/vhost1_access.log 86400" common
# Rotates errror log when it reaches 50M
ErrorLog "|/usr/IBM/httpserver/bin/rotatelogs /usr/IBM/httpserver/logs/vhost1_error.log 50M"
</virtualhost>
Note: while using this utility, always provide the full path to the rotatelogs executable and log file
location.
C. Websphere plug-in log [http_plugin.log]
It is advisable to keep this files logging at ERROR level. This can be specified in the plugin configuration
file [plugin-cfg.xml]. Look for the following line in the plugin config file and edit it accordingly to specify
the logging level and log file location.
<Log LogLevel="Error" Name="/opt/WebSphere/Plugins/logs/webserver1/http_plugin.log"/>
Since there is no in-built support to rotate this log, use the following unix commands to rotate the log.
Write a small script to do the following 3 steps.
1. Goto the directory where the plugin log is present
Cd /opt/IBM/HTTPServer/Plugins/logs/webserver1
2. Copy the plugin log to a new file with date
Cp http_plugin.log http_plugin_log.’date +%Y-%m-%d’
3. Now purge the old log file
Cat /dev/null >http_plugin.log
Once the script is made, place the script in crontab, to run it at a specified time.