AWStats on Debian might generate incomplete statistics. The script update.sh is executed regularly (once every 10 minutes via cron /etc/cron.d/awstats; you should really consider changing this to a bigger interval) in order to update/calculate the statistics (stored in /var/lib/awstats).
I changed the cron-file so that this script is executed once a day. However, the default installation of AWStats only considers /var/log/apache2/access.log (or some other log file) and does not cope with logrotate. So, if logrotate runs /var/log/apache2/access.log is rotated to /var/log/apache2/access.log.1(.gz) and on the next run AWStats only considers the content of the new rotated file. This issue becomes bigger when you increate the update.sh interval – in the default setup you can only loose up 10 minutes.
I reported this to Debian (Debian bug #706491) and proposed a possible solution: Do not use the logfile e.g. /var/log/apache2/access.log in the AWStats config files (e.g. /etc/awstats/awstats.conf: LogFile entry) directly, but use a wrapper script.
My script getlogs.pl can be used as follows: Do not use LogFile=”/var/log/apache2/access.log” in awstats.conf, but LogFile=”getlogs.pl /var/log/apache2/access.log”. If called with exactly one parameter (the logfile) it uses both access.log.1(.gz) (if exists) and access.log. My script can also be executed with “all” as the second parameter, then all existing rotated access.log*-files are used (in the right order and unpacked automatically). This might be useful if you want to build all statistics from scratch or you have bigger update.sh intervals than logrotate intervals. If the second parameter is missing, you can also use the USELOGFILES environent variable. This might be handy if you want to change it’s value more easily w/o editing all awstats.*.conf-files.
Alternative way: Run AWStats as a post-rotate script in logrotate.