Recommended Cron Jobs and Task Control Using Flags

[EIYEI Digital]

Cron discussions are so scattered that I thought this thread will help a lot of people (including me) to set cron jobs properly and share experiences doing so...

 

First, for all non-tech savvy users, a basic (very basic) view about cron jobs:

 

A Cron is a system (server) daemon (program) used to execute desired tasks (in the background) at designated times. It has 6 well defined parts as you can see:

 

01 04 1 1 1 /home/user/somedirectory/somecommand

 

Where the first 5 groups of digits, tell the cron when to execute the task or command...:

 

In the same order as the example above, from left to right, each group of digits tell:

minute (0-59 /* every minute), hour (0-23, 0 = midnight /* every hour), day (1-31 /* every day), month (1-12 /* every month), weekday (0-6, 0 = Sunday /* every weekday), command

 

So, in the example above somecommand will run every monday of january dated 1st at 4:01am

 

 

According to the WHMCS documentation you should run daily this: (http://docs.whmcs.com/Crons)

 

php -q /home/user/whmcs/crons/cron.php

 

So, in your cPanel > Cron Jobs section, you will have something like:

 

15 7 * * * php -q /home/user/whmcs/crons/cron.php > /dev/null 2>&1

 

Let's see that part by part:

 

15 7 * * * means that it will run on the minute 15, of the hour 7, every day, every month every weekday, in plain english, every day at 7:15am (server time).

 

It will execute the command php -q /home/user/whmcs/crons/cron.php

 

php -q means it will use php and will do it quietly (-q)

 

And the last bit > /dev/null 2>&1, tells the cron not to show/generate any output of the command, so you don't receive endless emails with the detail of the execution.

 

Done with the basic technical part... So for the practical day-to-day implementation..

 

 

Cron Flags (task control) (http://docs.whmcs.com/Cron_Tasks)

 

I've been struggling to run cron.php with the flag skip_backups, every time it runs, the backup gets generated.

 

That is php -q /home/user/whmcs/crons/cron.php skip_backups

 

Why would I like to do that? Well, I want to run the main cron once a day (or do you recommend something else) and backup my database twice a day...

 

 

I have seen a couple of posts where, for example, we want to skip suspensions during weekends, so you can deal with them during office hours mon-fri. Makes sense!

 

So, you would run, for your daily cron task something like:

 

daily:

15 7 * * * php -q /home/user/whmcs/crons/cron.php skip_suspensions

 

and for your suspensions alone:

 

suspensions:

15 8 * * 1-5 php -q /home/user/whmcs/crons/cron.php do_suspensions

 

 

Also, someone suggested to skip invoicing during weekends and do it the next working day (monday), so it would be something like (following the previous example):

 

daily:

15 7 * * * php -q /home/user/whmcs/crons/cron.php skip_suspensions skip_invoices

 

and for your suspensions+invoicing alone:

 

suspensions+invoicing:

15 8 * * 1-5 php -q /home/user/whmcs/crons/cron.php do_suspensions do_invoices

 

 

So, here my requests... if you'd like to help, leave your recommended cron tasks, everything from your experience will for sure help someone else...

 

And, why is my skip_backups flag not working? I checked the documentation and couldn't find any troubleshooting information on this... http://docs.whmcs.com/Cron_Job_Issues