XtraDB
Percona XtraDB is a storage engine for the MariaDB and Percona Server databases, and is intended as a drop-in replacement to InnoDB, which is one of the default engines available on the MySQL database.
Up until 10.1 of MariaDB, MariaDB server used Percona's XtraDB as the default storage engine. As of MariaDB 10.2, InnoDB engine is the default again, and not XtraDB.
XtraDB incorporates InnoDB's ACID-compliant design and MVCC architecture, and allows for a greater degree of tuning and scalability. The engine is also better suited to multi-core processing, which addresses some of the issues known to InnoDB.
