Percona Server is a fork of MySQL Community Edition, focusing on performance improvements.
Percona Server for MySQL is a rebase of MySQL's Community Edition server that focuses on implementing performance improvements that make the database scale better, and perform more consistently. These enhancements are available for MySQL 5.0, 5.1, 5.5, 5.7 and 8.0.
Percona Server comes with the XtraDB storage engine, which is an enhanced replacement of MySQL's InnoDB storage engine. In addition, Percona also includes the new MyRocks storage engine, developed in partnership with Facebook.
Percona Server is developed by the consulting company Percona, which also provides other helpful open source projects such as the Percona Toolkit, Percona XtraDB Cluster, and Percona Monitoring and Management. All software produced by Percona is 100% Free and Open Source.