Hi @pburnette, thanks for reaching out.
The free plugin doesn’t have scan rescheduling but will run later than scheduled if there aren’t many hits on your site. Obviously I can’t answer accurately on that as I don’t know your domain or visitor details but wp-cron jobs are triggered when PHP runs, so if you are seeing a performance hit it could be because more cron jobs for Wordfence (and possibly other plugins too) are all running at once. The best solution to keep cron jobs more on-schedule for sites is to set up a Linux cron job to trigger wp-cron jobs periodically, so they generally won’t all have overdue jobs at the same time.
If the above isn’t the issue and you’re having performance issues during scans, take a look at max_execution_time in your php.ini file. Wordfence’s scan only ever attempts to use half of this value by default but there have been known problems with timeouts when higher values than 60 are set, so it could be worth checking.
For a screenshot of my recommended Performance setting options inside the plugin too – Click Here.
Your WP_MEMORY_LIMIT could be set to 128M or 256M in wp-config.php. WooCommerce, for example, recommend 64M minimum, so if you also have many hits on the site at once especially during a Wordfence scan, a lower limit (like 40M I often see here) could be reached fairly easily. Also check your PHP memory_limit value matches or exceeds this value when making a change.
Many thanks,
Peter.
