Fix Cron Issues – Last Heartbeat Older Than X Minutes in Magento

This is probably one of the following two problems.

Your cron isn't being called properly

Often the cron.php just isn't called right. Either your cron.php isn't called at all or maybe it's called with insufficient rights or resources to execute properly. For example, executing the cron like this:

*/5 * * * * php -f /home/user/domain/public_html/cron.php

Might get very different results than expected because the user doesn't have the same rights as the user that runs the web server. And the PHP CLI has a different php.ini which may not have sufficiently large memory or execution time limits.

I often solve this by using wget or curl to call my cron or by editing the php.ini file that is used by my PHP CLI.

Magento is missing jobs

This happens if the settings under System > Configuration > System > Cron (Scheduled Tasks) are not configured corectly. This results in cron jobs being missed, even though the cron.php is called correctly. Make sure schedules are created and they schedule far enough ahead. And the "Missed if Not Run Within" is large enough.

The thing that is confusing about Magento’s cron services is that, while they do get invoked by the system cron, they are abstracted another level above it in a event/observer model that is common throughout Magento.

Once you understand this, the settings make more sense. If you want to see what they do exactly, their usage is pretty clear in app/code/core/Mage/Cron/Model/Observer.php, which is the observer that gets triggered for the default event in the crontab scope and in turn dispatches all the scheduled jobs.

• Generate Schedules Every: minutes interval for when Magento will schedule future jobs. It does not automatically schedule jobs during every execution.
• Schedule Ahead for: minutes in the future that jobs can be scheduled (added to cron_schedule database queue).
• Missed if Not Run Within: minutes past their scheduled time that jobs can still be executed before having their status set as missed, which comes into play if the queue is taking a long time to get through all the jobs that have been selected to run during the current execution of Mage_Cron_Model_Observer::dispatch() (their scheduled time is now or earlier).
• History Cleanup Every: minutes interval for when Magento will perform cleanup on the cron_schedule database queue, making reference to settings below regarding retention.
• Success History Lifetime & Failure History Lifetime: minutes in the future to leave records in the queue after they have reached these statuses. This comes into play if you want to see the result of past jobs since they may have placed resulting output into cron_schedule.messages, which can be especially helpful in the case of error status.