PHP Worning/ Memory Problem in Web Server

Problem: 

PHP Warning: require_once(): 

Unable to allocate memory for pool

Solution:

running Apache 2.2.15 + PHP 5.3.3 + APC php-pecl-apc-3.1.9 on CentOS / RHEL 6.4.

# vi /etc/php.d/apc.ini

; increased to 128M from 64M

apc.shm_size=128M

Don’t forget reboot the apache to apply changes:

# service httpd restart

If you would like to find out your APC memory usage and hit ratio:

# cp /usr/share/php-pecl-apc/apc.php /var/www/html

Edit /var/www/html/apc.php and set the admin password :

defaults('ADMIN_PASSWORD','NEW-PASSWORD');

Save and close the file. Fire a web-browser and type the url:

http://your-server-ip/apc.php