Drupal 7.7 Cron run failed. - Attempting to re-run cron while it is already running.

@poker10,
Can you clarify something please? Will the warning "Attempting to re-run cron while it is already running" be displayed even if cron takes less than 240 seconds (default) ? My cron always completes normally, and rarely takes more than 60 seconds, but I still occasionally see the warning. This behavior started after I migrated to a new server and moved from mysql 5.6 to msql 8.0. Thank you in advance.

@ohanm it depends on the cron settings, see: https://www.drupal.org/docs/7/setting-up-cron/overview → . If you have set-up your cron in Drupal, so the field "Run cron every" is set to something different from "Never", then the cron is being checked and run on each user request. So when one user triggers the cron, other user accessing the site in the same time (while it is still running) will trigger that warning. It is better to set the cron to run directly from an external trigger (for example from webhost directly accessing the cron.php link). Then it will not run on user requests and no warning would be logged. See: https://www.drupal.org/docs/7/setting-up-cron/overview#s-disabling-autom... →

@poker10,
Thank you for the perfect explanation, there is so much miss-information about this topic! It was set to every 1-hour. I've created an external cron task and no more warnings.