This tutorial will show you how to install Zend Optimizer on a server with RedHat like Linux operation systems.
Zend Optimizer is required by many scripts to run on your server decrypting and running them while increasing runtime performance.
This tutorial can be used when you run a server with CPanel or Plesk control panel with Apache server .

First download appropriate version of Zend Optimizer according to your server set from http://zend.com. Upload it to the server where will be installed using FTP client like Filezilla.
Unfortunately Zend does not provide a direct download so 'wget' cannot be used in this case.

Connect to your server via SSH using your favorite SSH client (for example Putty) and switch to super user. Go to the folder where the the file was uploaded and unpack it.
This can be done with the following command:

Then change the directory to the new extracted folder and start the installation script

You will see the 'Welcome to the Zend OptimizerInstallation" screen. Click 'OK', then 'EXIT' for the Zend License Agreement and then 'Yes' for the terms of the license?
For location for installing Zend Optimizer you can leave the default one.

the location of the 'php.ini' file is into the 'etc' folder

Then click 'YES' for the Apache server.
The next option is the full path for the apache control utility. By default it is : '/usr/sbin/apachectl' , but it can be on other place.
To find it you can use 'which' command on other console opened to the same server.

When you have the right location write it to the Zend Optimizer Installation

Click 'OK' on the configuration changes. Zend changing your php.ini file location so its better to make a note of this. And then you should see the finished successful installation screen.
Restart the Apache and check whether the Zend Optimizer is running.
After 'php -V' You should see similar to this message depending to the versions on your server:

With Plesk, by default there is a Ioncube loader installed that must be disabled.
This can be done as commenting the 'zend extension' in this file:

'/etc/php.d/ioncube-loader.ini'