To clean the Magento logs. The settings are under System > Configuration > Advanced > System > Log Cleaning.
If it hasn't been working, then you manually clean the logs.
cd /var/www/website.com/httpdocs/shell
display the size of the log files
php -f log.php status
clean the logs up :
php -f log.php clean To completely clear all logs from the database :
SET FOREIGN_KEY_CHECKS=0; TRUNCATE dataflow_batch_export; TRUNCATE dataflow_batch_import; TRUNCATE log_customer; TRUNCATE log_quote; TRUNCATE log_summary; TRUNCATE log_summary_type; TRUNCATE log_url; TRUNCATE log_url_info; TRUNCATE log_visitor; TRUNCATE log_visitor_info; TRUNCATE log_visitor_online; TRUNCATE report_viewed_product_index; TRUNCATE report_compared_product_index; TRUNCATE report_event; TRUNCATE index_event; SET FOREIGN_KEY_CHECKS=1;