The web host
Your web host provides you with the server space on which to run your site. Within many schools, your website will be hosted by your school. In other environments, you might need to arrange for your own web host by using a hosting company.
In selecting a web host, you need to be sure that they run software that meets or exceeds the recommended software versions.
Web server
Drupal is developed and tested extensively in an Apache environment. Drupal also runs on other web servers, including Microsoft IIS and Nginx.
PHP version
Drupal 7 will run on PHP 5.2.5 or higher; however, PHP 5.3 is recommended. The Drupal 8 release will require PHP 5.3.10.
MySQL version
Drupal 7 will run on MySQL 5.0.15 or higher, and requires the PHP Data Objects (PDO) extension for PHP. Drupal 7 has also been tested with MariaDB as a drop-in replacement, and Version 5.1.44 or greater is recommended.
Tip
PDO is a consistent way for programmers to write code that interacts with the database. You can find out more...