Magento Advanced/System/Cron Settings Guide

cronemailmagento-1.9schedule

Synopsis

So I wanted to confirm my understanding of the cron configurations with Magento; under the admin console System > Configuration > Advanced > System > Cron:

Generate Schedules Every #

I am unsure as to what this setting is about.

Schedule Ahead for #

I am assuming this will schedule # minutes ahead of crons. If the cron scheduler is configured in the cron tab to run every 5 minutes should this number also be configured to 5 or would Magento not reschedule jobs already scheduled?

Missed if Not Run Within #

This appears to me as if to say when a cron is scheduled to run and is not executed within # minutes it is set as 'missed'.

History Cleanup Every #

I imagine this should run through the cron_Schedule table and clear out all missed and executed schedules # minutes after they were executed/missed?

Success History Lifetime #

In regards to the previous configuration I assume this is going to clear out all successful schedules after # minutes?

Failure History Lifetime #

I assume this would clear out all missed schedules after # minutes? and then the history cleanup every #, success history and failure history settings are all entirely ambiguous.

Best Answer

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.

Related Solutions

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

Try this command:

wget -O /dev/null http://www.domain.com/cron.php

For debug purposes you can set every 3-4 minutes instead of every 10 minutes. If everything is working properly - in your database in table cron_schedule you will see cron tasks. If this table is clean - something went wrong.

upd.1

Don't be afraid, your cron runs like clockwork. In your table you see, that cron started successfully and completed successfully.

You got an error "Last heartbeat older than x minutes". In my opinion its very specific issue and related to some 3rd party extension. Try to search on your host this phrase. For example using SSH:

grep -rni 'Last heartbeat older than'

And upload full text of this method in your post.

Magento Admin Scheduled Backups Creating Multiple Backups – Fix

Couple of things here.

Never use the inbuilt backup tool. Its flawed in far too many ways to be useful. Instead, use conventional server tools to dump the DB and backup the files.

Eg. Some Magento specific tools for DB dumping

Or generic tools for MySQL dumping

automysqlbackup
xtrabackup - not recommended for novices

And for file backups, use things like rsync or tar to generate backups,

Eg.

Using tar

tar cvfz /path/to/backup.tgz /path/to/public_html \
  --exclude='/var/log' \
  --exclude='/var/session' \
  --exclude='/var/cache' \
  --exclude='/var/backup' \
  --exclude='/var/report' \
  --exclude='/media/catalog/product/cache'

Using rsync

rsync -vPa /path/to/public_html/ /path/to/backup_html/  \
  --exclude='/var/log' \
  --exclude='/var/session' \
  --exclude='/var/cache' \
  --exclude='/var/backup' \
  --exclude='/var/report' \
  --exclude='/media/catalog/product/cache'

You should never execute your cron via wget - you should be using the cron.sh wrapper to execute it,
```
* * * * * /bin/bash /path/to/public_html/cron.sh
```

Synopsis

Best Answer

Related Solutions

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

Magento Admin Scheduled Backups Creating Multiple Backups – Fix

Related Topic