I simulated a DOS attack the LOCI software to test the WordPress server under ISS 6. I have installed the ISA server and the server has no connection limit.
MySQL Server 5.1
PHP HP Version 5.2.16
The server is a RAID pe2650 xeon 2GB RAM 2 (4 cores)
The test was a real failure. A single PC with a 1MB DSL line (upload) makes 100% CPU to the server. Php-cgi.exe 10 processes eat up the cpu.
Solution 1. Using a plugin for caching pages and so the php will not work too :-).
It worked well for 2 minutes (10-15% CPU LOAD) in the third minute FAST-CGI ERROR.! arggghhh
I have not had a real attack, I'm just trying a DOS attack. I do not want to imagine a DDOS attack.
How I can do to make php go lighter?
Limiting the number and connections did not help to lower the CPU.
I understand that the php is working too much and should be cached queries to the bd.
One solution is to install the ISA server or psense in another machine to limit connections per IP and time but did not want to get to that extreme.
Thank you very much everyone!