Turn off WordPress HeartBeat to reduce bandwidth and CPU

Turn off WordPress HeartBeat to reduce bandwidth and CPU

By Strictly-Software

I recently noticed a spike in bandwidth and costs on my Rackspace server. The cost had jumped up a good $30 from normal months.

Now I am still in the process of finding out why this has happened but one thing I did come across was a lot of calls to a script called /wp-admin/admin-ajax.php which was happening every 15 seconds.

Now this is the sign of WordPress's HeartBeat functionality which allows the server and browser to communicate and I quote from the inmotionhosting.com website, HeartBeat

allows WordPress to communicate between the web-browser and the server. It allows for improved user session management, revision tracking, and auto saving.

The WordPress Heartbeat API uses /wp-admin/admin-ajax.php to run AJAX calls from the web-browser. Which in theory sounds awesome, as WordPress can keep track of what's going on in the dashboard.

However this can also start sending excessive requests to admin-ajax.php which can lead to high CPU usage. Anytime a web-browser is left open on a page using the Heartbeat API, this could potentially be an issue.

Therefore I scanned my log files and found that my own server IP was making calls to a page every 15 seconds e.g

62.21.14.247 - - [11/Nov/2014:15:00:20 +0000] "POST /wp-admin/admin-ajax.php HTTP/1.1" 200 98 "http://www.mysite.com/wp-admin/post.php?post=28968&action=edit&message=1" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.124 Safari/537.36" 0/799585
62.21.14.247 - - [11/Nov/2014:15:00:35 +0000] "POST /wp-admin/admin-ajax.php HTTP/1.1" 200 98 "http://www.mysite.com/wp-admin/post.php?post=28968&action=edit&message=1" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.124 Safari/537.36" 25/25540888

I checked my browser (Chrome) which I do leave lots of windows open for ages, multi tasking :) , and I found that I had left open a post edit window in WordPress. This was causing the HeartBeat to call the script every 15 seconds.

Now I don't know that this is the ONLY reason for my increase in Bandwidth and obviously CPU due to all the HTTP requests but I am guessing it made up a big part of it.

Therefore I decided to turn off the HeartBeat functionality.

I have already disabled auto saving and revisions as I don't need that functionality so I am going to see what happens - hopefully my costs will go down!

Turning Off WordPress HeartBeat

To turn off the HeartBeat functionality go to your themes functions.php file and put the following code at the top of it.

// stop heartbeat code
add_action( 'init', 'stop_heartbeat', 1 );

function stop_heartbeat() {
        wp_deregister_script('heartbeat');

}

So I will see what happens with this turned off. So far not a lot.

However if you do notice a spike in your Bandwidth or CPU and you use WordPress check you haven't left a page open in your browser that would be causing the HeartBeat function to call the /wp-admin/admin-ajax.php every 15 seconds!

Problem with SFTP after new router installation

Problem with SFTP / SSH after new router installation

This may seem like an obvious one but it can catch you out if you are not aware of the implications of having a new IP address assigned to your house's broadband. You may have moved your laptop to a new house or using a new wifi system to connect to the Internet.

More commonly you may have been given a new or upgraded router by your ISP provider.

Even if you are told the IP address has not changed by BT, Virgin, Sky, Verizon or whoever is giving you the new router you should do a check on any of the many IP checking pages out there on the web.

E.G this script shows you your current IP and ISP details.


Why is this important?

Well if you have your own server being hosted by a company e.g a cloud server somewhere and you have installed DENY HOSTS to block hacking attacks then you might find that you cannot SFTP (Secure FTP) into your server anymore or that using Putty and SSH to access your remote server suddenly stops working for no apparent reason. Obviously you want to access your server so the problem needs fixing.

Symptoms of an IP change causing problems include:

• Your server reporting error messages such as "server unexpectedly closed the connection."
• When you change the file transfer settings to simple FTP from SFTP you can access the server but then experience timeout errors or when the list directory command is run nothing happens.
• Not being able to use Putty or another SSH tool to connect to your server.
• Not having changed any settings on your computer but not being able to connect to your server anymore.

Solution to IP change:

• Check and write down your new IP address.
• Log into your server through WebMin or a web based system or from another computer that hasn't had an IP change.
• Check your DENY HOSTS list to see if your IP address is listed and if so delete the record.
• Add your new IP address in the ALLOW HOSTS list.
• Re-start your server. 

If you don't know how to do this read the 3rd part of my Wordpress Survival Guide about security.