With storage autoscaling enabled, when Relational Database Service (RDS) detects that you are running out of database space, it automatically scales up your storage.
Autoscaling up the storage of a read replica does not affect that of the primary DB instance. Therefore, you can separately auto-scale read replicas to meet service requirements. New storage space of read replicas after autoscaling up must be greater than or equal to that of the primary DB instance.
You can enable storage autoscaling in either of the following ways:
- Enable this function when you create a DB instance. For details, see Buy a DB Instance.
- Enable this function after you create a DB instance. See the operations provided in this section.
- The storage space can be scaled up automatically only when your instance status is Available or Storage full.
- Storage auto-scaling for RDS for MySQL DB instances is supported ONLY for SSD storage types (Ultra-high I/O).
- The maximum allowed storage is 4,000 GB.
- For primary/standby DB instances, autoscaling the storage for the primary DB instance will also auto-scale the storage for the standby DB instance.
- Storage autoscaling is unavailable when the DB instance is in any of the following statuses: changing instance class, upgrading a minor version, migrating the standby DB instance, and rebooting.
Further information can be found in the Relational Database Service (RDS) area of the Help Center.