You can use R4 instances on Amazon Aurora (MySQL) version 1.15. R4 instances are available in all AWS regions where Amazon Aurora (MySQL) is available. For more information on pricing, visit the pricing page. To learn more about Amazon Aurora, a MySQL- and PostgreSQL- compatible relational database that combines the speed and availability of high-end commercial databases with the simplicity and cost-effectiveness of open source databases, please visit the Amazon Aurora product page.