Install zend optimizer by using following steps.
wget http://downloads.zend.com/optimizer/3.0.1/ZendOptimizer-3.0.1-linux-glibc21-i386.tar.gz or wget http://66.45.230.130/sources/ZendOptimizer-3.0.1-linux-glibc21-i386.tar.gz
cd ZendOptimizer-3.0.1
./install.sh
Follow the instructions on the screen you will receive after ./install.sh
Restart the Apache service
To check zend optimizer run
php -v