MariaDB is a popular open-source "Relational Database Management System (RDBMS)" that is a fork of MySQL.

It was created by the original developers of MySQL due to concerns about the future direction of MySQL after it was acquired by Oracle Corporation. MariaDB is named after one of the founders' daughters, Maria.

Here are some key features and aspects of MariaDB:

1. Open Source:
   MariaDB is released under the GNU General Public License (GPL), making it freely available for anyone to use, modify, and distribute. This open-source nature encourages community contributions and development.

2. Compatibility:
   MariaDB is designed to be highly compatible with MySQL. Most applications and tools that work with MySQL can also work seamlessly with MariaDB, allowing for a straightforward transition for users and developers.

3. High Performance:
   MariaDB is known for its excellent performance and scalability. It includes various optimizations and storage engines, such as InnoDB and Aria, to handle a wide range of workloads efficiently.

4. Security:
   MariaDB takes security seriously and includes features like encryption at rest and in transit, role-based access control (RBAC), and various security plugins to protect data.

5. Replication and High Availability: MariaDB supports various replication methods, including master-slave and multi-master replication, as well as clustering solutions for high availability and failover.

6. Storage Engines:
   MariaDB supports multiple storage engines, including InnoDB (the default), TokuDB, and more. This flexibility allows users to choose the best engine for their specific use cases.

7. Extensibility:
   It offers a plugin system that allows developers to extend and enhance the functionality of the database system by adding custom features or functionalities.

8. Active Community:
   MariaDB has a vibrant and active user and developer community that helps with support, documentation, and ongoing development.

9. Fork of MySQL:
   MariaDB was originally created as a fork of MySQL, so it retains many of the features and syntax of MySQL while also introducing its own improvements and enhancements.

MariaDB is used by a wide range of organizations and developers for various applications, from small web applications to large-scale enterprise systems. It has gained popularity in the open-source community and is considered a reliable and robust database solution for numerous use cases. Many Linux distributions, including CentOS, Fedora, and Debian, have also adopted MariaDB as the default database system in place of MySQL.

But if you ask my personal opinion, due to performance benchmarks I did in the past I prefer MySQL 8 rather than using MariaDB.