How does setting open_basedir affect the performance of a website?

Setting open_basedir can affect the performance of a website by restricting the directories from which PHP scripts can be executed. This can lead to slower loading times as the server has to check if the requested file is within the allowed directories. It is important to carefully choose the directories to restrict to minimize the impact on performance.

// Example of setting open_basedir in PHP
ini_set('open_basedir', '/var/www/html:/tmp');