Httpd / mysql consistently taking up 500% of CPU

We're on a VPS w/ CentOS 5 with cPanel + WHM 11 latest

We started noticing last night that httpd and occasionally mysql keeps consistently peaking in the 500%'s of CPU usage, so much so that our host kept suspending our account because of it.

We've had two server teams look into it and neither can identify why this is happening.

We haven't been experiencing any influx of traffic, and nothing major has changed code wise.

We're seeing lots of these in our apache error log

[Mon Nov 16 21:53:24 2009] [error] [client 65.55.207.22] Request exceeded the limit of 200 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.

I can't find any redirect loops in the code, and up until now our .htaccess config hasn't been causing any problems:

DirectoryIndex home.html index.htm index.html index.php


RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.(.*) [NC]
RewriteCond %{HTTPS}s<>%1 ^(on(s)|offs)<>(.*)
RewriteRule ^(.*) http%2://%3/$1 [L,R=permanent]

RewriteRule ^c/([0-9]+)$ /main/?p=$1 [R=301,L]


Addhandler application/x-httpd-php5 .html .inc
AddHandler application/x-httpd-php5 .inc .html

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

I realize this isn't very much info, and it's hard to say without digging in, but wanted to throw this out there if anything raised any red flags or if you have any suggestions on where we could further look into.

From serverfault Susan

• To start with, have a look at your access log for that client and see what it's requesting. That should at least give you an idea what may be causing the redirect.

  Next, try fetch that URL using Perl's lwp-request:

  lwp-request -esSd http://the/offending/url
  

  That should get you 90% of the way to isolating where the problem is.

  From Rudedog