Bestrafung

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Apr 2, 2012
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I have a cPanel VPS setup on CentOS 5.10 running under Hyper-V (Windows Server 2008 R2). Everything was running fine until recently when we installed a chat addon to a client's vBulletin forums. Anytime the chat addon is used the server load skyrockets. While looking into this I see that we are getting a large amount of CPU usage in general for PHP and MySQL. I have confirmed it's not a memory or swap issue. Does anyone have any ideas what could be causing the high usage or how to reduce it?

Here's some of the information from WHM's top processes:
User Domain % CPU Process
user1 user1.com 48.0
PHP:
 <defunct>
user1 	user1.com 	47.0  		[php] <defunct>
user2 	user2.com 	46.0  		[php] <defunct>
user2 	user2.com 	42.0  		[php] <defunct>
user3 	user3.com 	38.0 	 	[php] <defunct>
user2 	user2.com 	38.0 	 	/usr/bin/php /home/user2/public_html/vbshout.php

There's a dozen or so more in the 15-25% range as well.

Apache/2.2.26
PHP 5.3.28


EDIT: I've heard that dynamic disks in Hyper-V VMs can introduce I/O issues over fixed disks. Does anyone have any experience with this and whether or not it could be leading to the high load? I suspect that the dynamic disk is causing I/O wait or load with mysql which is in turn causing high CPU usage with PHP, but it's just a theory. I plan to convert the system to a fixed disk as soon as I have more scheduled downtime anyway I was just curious if anyone had any experience with this.
 
Last edited:

cPanelMichael

Technical Support Community Manager
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Apr 11, 2011
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Everything was running fine until recently when we installed a chat addon to a client's vBulletin forums. Anytime the chat addon is used the server load skyrockets.
Hello :)

Have you checked with the developers or support team for this plugin to rule out any issues with the application itself? It's possible there is a flaw in the application that results in high load under heavy usage.

Thank you.