Failed loading /usr/lib/php/zend/ZendOptimizer-5.3.so: cannot open shared object file: No such file or directory

Recently I upgraded PHP 5.2 to PHP 5.3 on a CentOS Linux server because of a PHP 0day and noticed an error complaining about ZendOptimizer-5.3.so which is the library loaded into PHP. After some research I found out that it doesn’t look like Zend Optimizer is available for PHP 5.3 on CentOS Linux and will not be available for PHP 5.3 period. Not a big deal in my scenario as I was using it as well as PHP eAccelerator. This error is easily resolved as long as you do not require the php-zend-optimizer package so if that is the case follow the directions below to resolve the error.

Apache Error Logs Complaining About ZendOptimizer-5.3.so:

When looking in the /usr/lib/php/zend/ directory there were numerous other ZendOptimizer .so files which are shown in the below example output.

ZendOptimizer .SO Library Files Available:

As you can see there are numerous versions available except for the ZendOptimizer-5.3.so version we need. To resolve the issue remove php-zend-optimizer and restart Apache as shown in the below example.

Display & Remove php-zend-optimizer Using Yum On A CentOS Linux Server:

Once removed restart Apache using the httpd init.d script. Once Apache is restarted you can verify that Zend Optimizer has been removed by checking your PHP version as shown in the below example.

Verify PHP Version On Linux Server:

You should no longer receive the error. If you require PHP Zend Optimizer then you will likely need to build it from source are stay on PHP 5.2. I would recommend not staying with PHP 5.2 and finding another solution because of all of the security holes with PHP 5.2.X.