FAQ

This plugin uses the WP-cron to schedule events which synchronise the data. WP-cron is the system built into WordPress to handle the scheduling of time-based tasks and to simulate a system-cron. However, WP-cron is not always reliable on low traffic sites because it needs traffic to call the scheduled events. See: Understanding WP-Cron Scheduling.

If your site does not get visits regularly and you really want the tasks to run on time – take a look at: Hooking WP-Cron into the System Task Scheduler.

No, you only need to insert the license at the site which is your monitor.

Sites Monitor only uses a few API’s and sends a minimal amount of data to the site which acts as the monitor. You can configure at what interval this is done: per hour, day, twice a day or weekly. The monitor site itself does not need to fetch or crawl for data.
We’ve been using this plugin on quite a lot of sites and have not seen performance regressions.