Apache, FTP, mail and other system services write information on their functioning to log files. These files are periodically analyzed by the statistics utility that parses logs and inserts the resource usage data into the psa database.

Two other utilities, Webalizer and AWstats, also parse the services logs and generate HTML files with the statistical data.

Details about where the log files reside and how the utilities process them are given in this chapter.

System Services Logs

System services logs contain traffic usage data and operational details that might be useful for troubleshooting (for example, errors and access information).

Logs of the two services that are responsible for Plesk operation, sw-cp-server and sw-engine, are the following:

• /var/log/sw-cp-server/error_log - the error log of the sw-cp-server (web server nginx) .
• /var/log/sw-cp-server/sw-engine.log - the error log of the sw-engine (PHP process manager PHP-FPM).

The Plesk log file is the following:

/var/log/plesk/panel.log - contains PHP messages and messages related to the operations of Plesk.

Domain logs are stored in $HTTPD_VHOSTS_D/system/ <domain_name> /logs/. These are logs produced by web, FTP and mail services for each domain. Usually, the $HTTPD_VHOSTS_D variable’s value is /var/www/vhosts. Also, $HTTPD_VHOSTS_D contains a different path if you changed the location of virtual host directories using the transvhosts.pl utility.

To save disk space, Plesk rotates logs: it removes the information written before a specified date or the least relevant information when the log size reaches a limit. For more information on logs rotation, see the section Log Rotation.

Processing Statistics

Once a day, Plesk runs the statistics utility. This gets the statistical data from the services log files, calculates daily traffic usage values for each domain and customer, and writes these values to the DomainsTraffic and the ClientsTraffic tables of the psa database. You can also run the statistics utility manually to calculate statistics for all domains or a particular domain.

Webalizer and AWstats are third-party utilities that represent statistical information from log files in the HTML format. These utilities store the files for each domain in the subdirectories of /var/www/vhosts/<domain_name>/statistics. You can view HTML statistics in the Plesk GUI or make Plesk send them to your email address. For instructions on how to set up automatic sending of resource usage reports, see the section Resource Usage Reports.

In addition, you can recalculate statistic for previous months using the AWstats utility. For instructions on how to do this see the section Recalculating Statistics for Previous Months.