FSSE.INFO: mod

http://httpd.apache.org/docs/1.3/logs.html
http://httpd.apache.org/docs/2.0/logs.html
http://httpd.apache.org/docs/2.2/logs.html
http://httpd.apache.org/docs/2.2/mod/mod_log_config.html
http://linux.die.net/man/3/strftime

mod_log

apache httpd mod_log logs http access and errors

log format

you can customise the log format

LogFormat "%h %l %u %t \"%r\" %>s %b" common

conditional log

you can conditionally omit certain entries

 # Mark requests for the robots.txt file
SetEnvIf Request_URI "^/robots\.txt$" dontlog
# Log what remains
CustomLog logs/access_log common env=!dontlog

log rotate

normal logrotate does not work since apache locks the files open

but you can manually truncate

$ > /var/log/access_log

or shorten them

$ tail -10000 /var/log/access_log > /var/log/access_log

without restarting apache httpd otherwise you must use

piped log

rotatelogs is an apache utility you can pipe logs to and rotate them
(in seconds)
hourly (12 logs/day)

CustomLog "|/usr/local/apache/bin/rotatelogs /var/log/access_log.%I 3600" common

hourly (24 logs/day)

CustomLog "|/usr/local/apache/bin/rotatelogs /var/log/access_log.%H 3600" common

daily (7 logs/week)

CustomLog "|/usr/local/apache/bin/rotatelogs /var/log/access_log.%w 86400" common

vhost log

to create one log file for all vhosts add %v to your access LogFormat

LogFormat "%v %h %l %u %t \"%r\" %>s %b" common

and must then use split-logfile to split into separate logs

NOTE: You cant do this with your vhost error logs

REFERRERS
ApacheModules

FSSE.INFO : ModLog