Like most ìmodernî content management systems, WordPress relies on a MySQL Database to store content. In most cases, this database is rather small. Only text like Posts, Pages, Custom Post Types, and general settings are stored in this database. Images and other files are stored on the server by default. As sites grow, so does the content and, consequently, so does the number of queries to the database. MySQL is a very resilient system, but like most things, there is a point when it canít get any bigger, faster, or safer.