max
Specifies the maximum storage (in GiB) that Amazon RDS can automatically scale to for this DB instance. By default, Storage Autoscaling is disabled. To enable Storage Autoscaling, set max_allocated_storage to greater than or equal to allocated_storage. Setting max_allocated_storage to 0 explicitly disables Storage Autoscaling. When configured, changes to allocated_storage will be automatically ignored as the storage can dynamically scale.