Bug High CPU Usage

[racersimage]

Hey there, I received the following email from my webhost this morning.

Hello,

It has come to our attention that your hybrid server is consistently using more than the allotted 1 CPU core. Your hybrid comes with 1 Guaranteed CPU core. When you push over a load average of 1 (it's consistently running between 2-3) that means that your sites are using beyond the 1 Guaranteed CPU core that comes with your plan. While we allow you to burst beyond the 1 Guaranteed CPU, if you are using 2-3 times the CPU time on the hardware node, this is a sign that you need to either buy more Guaranteed CPU cores on your Hybrid Plan or upgrade to a Dedicated server.

A dedicated server may be more cost effective in the long run. Each additional core adds $25/month to your invoice. Based on your Grove graphs, you need to add at least one additional core to your hybrid plan.

This CPU usage is clearly being caused by the CPU intensive dbseo script:

/usr/local/lsws/fcgi-bin/lsphp5:home/nascartr/public_html/community/dbseo.php

Please let me know how you'd like to proceed.


Kind regards,

Nick Teeple
Managed Dedicated Servers | Managed VPS Web Hosting | WiredTree

Toll Free: +1 866-523-8733
Local: +1 312-447-0510
Fax: +1 312-447-0514

https://www.facebook.com/WiredTree
https://www.twitter.com/WiredTree
https://www.wiredtree.com/Google+

Wondering what I can do about this, I never had this trouble with vBSEO so maybe there's a tweak I can do to remedy this problem?

 

[Fillip H.]

The only thing you can do is to ensure that you have a Datastore cacher enabled in vB's config.php; either Memcache, APC, XCache or eAccelerator will work. That will use RAM to cache as much data as possible to save CPU time.

Keep in mind that because of the .htaccess redirect, literally every single request your site receives is piped through dbseo.php. If you have installed any new mods since you switched from vBSEO to DBSEO, and this new mod caused an issue, the statistics would still show dbseo.php as the culprit, as it essentially becomes the source for any other script ran.

As evidence that what I'm saying is legitimate: The actual dbseo.php file itself does almost nothing. A lot of DBSEO's core mechanics exist in /dbtech/dbseo/includes/class_core.php. Thus, if your host's resource monitor had the ability to detect the real source of high CPU load, and DBSEO was the cause, it would show the class_core.php file as the resource hog.

In other words, try disabling all mods you've installed or updated since your switch from vBSEO to DBSEO. It's likely one of them is the culprit, as others have reported that (especially later versions) DBSEO is pretty much identical or faster than vBSEO in terms of CPU usage. Our own tests on this site showed a 33% reduction in CPU usage after switching, and that was before multiple optimisation passes had been done.

 

[racersimage]

The only new addition I have made is the Ajax Threads modification. Could that be the cause?

 

[Fillip H.]

It shouldn't, but it's worth giving disabling it a try