======Install APC====== we need the pecl command so we can download and install APC from the repositories. * use yum to install pecl <code> yum install php-pear php-devel httpd-devel </code> * install APC <code> pecl install apc </code> at the end you can read <file> Build process completed successfully Installing '/usr/lib/php/modules/apc.so' install ok: channel://pecl.php.net/APC-3.0.19 configuration option "php_ini" is not set to php.ini location You should add "extension=apc.so" to php.ini </file> open php.ini, find <file> ;;;;;;;;;;;;;;;;;;;;;; ; Dynamic Extensions ; ;;;;;;;;;;;;;;;;;;;;;; </file> add this line under it extension=apc.so save & exit, and restart the service <code> /etc/init.d/php_cgi restart </code> for apache <code> /etc/init.d/httpd restart </code>