MySQL vs MariaDB
MariaDB is a community-developed fork of the MySQL relational database management system intended to remain free under the GNU GPL. Some of the original developers of MySQL forked it due to concerns over its acquisition by Oracle Corporation. Its lead developer is Michael "Monty" Widenius, one of the founders of MySQL AB. MariaDB is named after Monty's younger daughter Maria, similar to how MySQL is named after his other daughter My.
MariaDB version numbers follow the MySQL's numbering scheme up to version 5.5. Thus, MariaDB 5.5 offers all of the MySQL 5.5 features. After the 5.5 version, MariaDB developers decided to start a branch numbered 10, as an attempt to make it clear that MariaDB 10.0 will not import all features from MySQL 5.6.
In 2010, MySQL was acquired by the Oracle Corporation. At that time, one of the original developers, Michael “Monty” Widenius, felt that the Oracle Corporation had a conflict of interest between MySQL and their Oracle database. In response to this, he decided to create a fork of the project named MariaDB. Since Oracle is backing MySQL and has a firm foundation, it continues to be the leader. However, MariaDB offers some compelling reasons for why people may want to switch databases.
Database Structure and Indexes
MySQL is a relational database with an ANSI-standard information schema which consists of tables, columns, views, triggers, cursors, and more. Since MariaDB is a fork of MySQL, the database structure and indexes of MariaDB are the same as MySQL. This allows you to switch from MySQL to MariaDB without having to alter your applications, since the data and data structures will not need to change.