MariaDB is a community-developed, cross-platform, open-source, and commercially supported fork of the MySQL relational database management system (RDBMS). MariaDB was intended to be a drop-in replacement and maintain high compatibility with MySQL. However, in later versions with new features, this is no longer the case.
Back in 2010, when Oracle acquired Sun Microsystems, Widenius, the original developer of MySQL forked the open-source project to create MariaDB. MariaDB is named after Widenius’ younger daughter, Maria following the convention of MySQL which was named after his other daughter.
MariaDB is included in several Linux distributions and is the default database in distros such as Arch Linux, Manjaro, Debian 9+, Fedora 19+, Red Hat Enterprise Linux (RHEL 7+), CentOS 7+, Mageia 2+, openSUSE 12.3+, SUSE Linux Enterprise Server (SLES 12+), OpenBSD 5.7+, and FreeBSD.