fcgid is apache fastcgi implementation module that is really a fast apache handler.It is an alternative to apache mod_cgi and mod_cgid apache handler module but so much faster and with high performance .What it really does as I know it caches the php functions and classes and remain them active untill the time they are requested from clients and so that it wont load them again and consume cpu processes also it caches mysql queries and all of those will lower the amount of cpu usage and also that automaticly will reduse HArd i/o wait time so that this will make the load of the server so low and every thing will be served to clients from ram that is so faster than hard drives.
it is an alternative to mod_php with much more faster with a similar performance.
In this tutorial you will gongi to find out how to compile and make it enabled on directadmin control panel customized compiled apache .
So lets get started
run the following command into your secure shell(ssh);

Go to the custombuild directory which is provided by directadmin and open it using the nano editor

in the case that you recieved error that nano is not understood by your linux you must have it installed
for installing nano just use yum

you will recieve a confirmation yes/no, surly type yes and enter to continue installing nano editor.
You must make this option to yes in options.conf
php5_cgi=yes
on the very first lines there should be something like this after you modify this options.conf

after that build php by runngi the following command

then you should add mod_fcgid to apache
for doing so you should intruct apache to load mod_fcgid on its config file which is httpd.conf
by the following command you will open htpd.conf by nano editor

add the following codes that are fcgid config lines to httpd.conf

Then after that we should go to the virtualhost template to modify virtual hosts that is located at
/usr/local/directadmin/data/templates
we will create a folder named custom
we wil copy thise files into this folder from templates

for creating the folder named custom and to copying these 4 files we will use the following command:

comment out the lines that are commented as commented here on each of these 4 virtual_hosts2

and then insert the following lines of codes just before the start of codes written above

crate fcgid.sh shell script;

and then pase these codes into fcgid.sh

create domain_create_post.sh in the smae fodler you already created fcgid.sh shell script and paste the following code into that shell script that you already created

copy php.ini to /usr/local/directadmin/scripts/custom/ directory

edit the php.ini that you have just copied with nano text editor

and then search for open_basedir that is normally commented out by default by a semicolon
for searching use CTRL + W and hen type the text to search that in this case it should be open_basedir
remove the semicolon and assign it PHPCFG_BASEDIR:/tmp:/var/tmp

after that run the bellow command:

THanks

http://www.wingfoss.com/content/install-mod-fcgid-on-direct-admin