Starting today, you can use Aurora Auto Scaling to automatically add or remove Aurora Replicas in response to changes in performance metrics specified by you. Aurora Replicas share the same underlying volume as the primary instance and are well suited for read scaling. With Aurora Auto Scaling, you can specify a desired value for predefined metrics of your Aurora Replicas such as average CPU utilization or average active connections. You can also create a custom metric for Aurora Replicas to use it with Aurora Auto Scaling. Aurora Auto Scaling adjusts the number of Aurora Replicas to keep the selected metric closest to the value specified by you. For example, an increase in traffic could cause the average CPU utilization of your Aurora Replicas to go up and beyond your specified value. New Aurora Replicas are automatically added by Aurora Auto Scaling to support this increased traffic. Similarly, when CPU utilization goes below your set value, Aurora Replicas are terminated so that you don’t pay for unused DB instances.