Apache increase loglevel – Increasing Apache logged data for better statistic analysis

Tuesday, 1st July 2014

Reading Time: 2minutes

In case of development (QA) systems, where developers deploy new untested code, exposing Apache or related Apache modules to unexpected bugs often it is necessery to increase Apache loglevel to log everything, this is done with:


LogLevel debug

LogLevel warn is common logging option for Apache production webservers.


in httpd.conf is the default Apache setting for Log. For some servers that produce too many logs this setting could be changed to LogLevel crit which will make the web-server log only errors of critical importance to webserver. Using LogLevel debug setting is very useful whether you have to debug issues with unworking (failing) SSL certificates. It will give you whole dump with SSL handshake and reason for it failing.

You should be careful before deciding to increasing server log level, especially on production servers.
Increased logging level puts higher load on Apache webserver, as well as produces a lot of gigabytes of mostly useless logs that could lead quickly to filling all free disk space.

If you  would like to increase logged data in access.log / error.log, because you would like to perform versatile statistical analisys on daily hits, unique visits, top landing pages etc. with Webalizer, Analog or Awstats.

Change LogFormat and CustomLog variables from common to combined.

By default Apache is logging with following LogFormat and Customlog

LogFormat "%h %l %u %t "%r" %>s %b" common
CustomLog logs/access_log common

Which will be logging in access.log format: – jericho [10/Oct/2000:13:55:36 -0700] "GET /apache_pb.gif HTTP/1.0" 200 2326

Change it to something like:


LogFormat "%h %l %u %t "%r" %>s %b "%{Referer}i" "%{User-agent}i"" combined CustomLog log/access_log combined

This would produce logs like: – jericho [10/Oct/2000:13:55:36 -0700] “GET /apache_pb.gif HTTP/1.0” 200 2326 “http://www.example.com/start.html” “Mozilla/4.08 [en] (Win98; I ;Nav)"


Using Combined Log Format produces all logged information from CustomLog … common, and also logs the Referrer and User-Agentheaders, which indicate where users were before visiting your Web site page and which browsers they used. You can read rore on custom Apache logging tailoring theme on Apache's website

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