Scaling Storage Space

Scenarios

If the storage space is not enough for your workloads, you can scale up storage space of your DB instance.

A DB instance needs to preserve at least 15% of its capacity to work properly. The new minimum storage space required to make this instance available has been automatically calculated for you. You are advised to set alarm rules for the storage space usage by referring to Setting Alarm Rules.

Constraints

**Table 1** Constraints
Phase	Constraints	Duration
Storage scale-up	You can scale up storage space only when your account balance is greater than or equal to $0 USD. There is no downtime during storage scale-up. The maximum allowed storage is 4,000 GB. There is no limit on the number of scale-ups. If you want to increase the storage upper limit, submit a service ticket. The maximum allowed storage space for some RDS for SQL Server DB instances is 2,000 GB because of constraints of the windows disk size. The actual maximum allowed storage space depends on the information displayed on the console. For primary/standby DB instances, scaling up the primary DB instance will cause the standby DB instance to also be scaled up. You cannot reboot or delete a DB instance that is being scaled up. If you scale up the storage of a DB instance with disk encryption enabled, the new storage will still use the original key for encryption.	The scale-up takes 3 to 5 minutes.
Storage scale-down	To scale down the storage space of a DB instance, submit a service ticket. The storage space of a DB instance can be scaled only when the instance is Available. Only instances whose storage type is ultra-high I/O, cloud SSD, or extreme SSD can be scaled down. Scaling down storage space of a DB instance during peak hours may fail due to insufficient storage space. Scale down storage space during off-peak hours. You cannot scale down the storage space of a DB instance with publication and subscription enabled. You cannot scale down the storage space of a read replica or a cluster instance with read replicas. Before scaling down storage space of a DB instance, ensure that all service databases have at least one automated full backup. Storage scale-down may interrupt workloads for several minutes. To prevent scale-down failures, do not delete or create databases during a scale-down. If storage autoscaling is enabled and the target shrink size is set below the threshold specified for storage autoscaling, the system will automatically increase the storage again after the shrink operation. Therefore, select an appropriate shrink size for scale-down.	During off-peak hours, the time required for scaling down the storage space depends on the resource usage and data volume of the DB instance. If there is much data, it takes much more time. When there are enough I/O and CPU resources, it takes about 9 hours to scale down a DB instance with 1 TB of data. If the scale-down takes an extended period of time, submit a service ticket.

Procedure

Click in the upper left corner and select a region.
Click in the upper left corner of the page and choose Databases > Relational Database Service.
On the Instances page, locate the target DB instance and choose More > Change Storage Space in the Operation column.

Or use either of the following methods:
- Click the target instance name to enter the Summary page. In the Storage & Backup area, click Change Storage Space.
- If the instance storage is full, locate the instance on the Instances page and click Scale in the Status column.
On the displayed page, specify the new storage space and click Next.

You can increase or decrease the storage by at least 10 GB. Enter a value that is a multiple of 10. The instance supports a storage space range from 40 GB to 4,000 GB.

The maximum allowed storage space for some RDS for SQL Server DB instances is 2,000 GB because of constraints of the windows disk size. The actual maximum allowed storage space depends on the information displayed on the console.

Select a time to schedule the change. (To use this function, submit a service ticket.)
- Immediate: The change is applied immediately after the request is submitted.
- During maintenance window: If this option is selected, you can view the task details later on the Scheduled Tasks page. For details, see Viewing a Task. You are advised to set the maintenance window to off-peak hours.
Confirm the information.
- If you need to modify your settings, click Previous.
- If you do not need to modify your settings, click Submit for a pay-per-use instance or click Pay Now for a yearly/monthly instance.
Check the result.

On the Instances page, the status of the DB instance will be Scaling up or Scaling down. After a while, click the instance name and check that the new value for storage space appears on the Summary page.