Change the specifications of an ApsaraDB RDS for SQL Server instance - ApsaraDB RDS

This topic describes how to change the specifications of an ApsaraDB RDS for SQL Server instance to improve instance performance and resolve the storage bottlenecks caused by business growth. The specifications that you can change include the performance level (PL) of the storage type, instance type, and storage capacity. For example, you can upgrade the PL of the Enterprise SSD (ESSD) storage type from PL1 to PL2. Storage capacity expansion without data loss is supported for specific RDS instances, which does not cause service interruptions.

Note

For more information about how to change the specifications of a serverless RDS instance, see Change the scaling range of RCUs for a serverless ApsaraDB RDS for SQL Server instance and Expand storage capacity.

Changable specification items

The following table describes the specification items that you can change for an RDS instance. The modification of the following items does not change the endpoints of the RDS instance. To increase the read capability of your database system, you can create read-only RDS instances and enable read/write splitting to offload read requests from the primary RDS instance. This applies if your primary RDS instance runs RDS Cluster Edition.

Specification item	Description
Database engine version	You can upgrade the database engine version of your RDS instance to a later version.
RDS edition	You can upgrade the RDS edition of your RDS instance from RDS Basic Edition to RDS High-availability Edition or RDS Cluster Edition or from RDS High-availability Edition to RDS Cluster Edition.
Instance type	If you want to change the instance type without the need to change the instance family, you can change instance specifications. For example, you can change instance specifications to change the general-purpose instance type from `mssql.s2.medium.s2` to `mssql.s2.large.s2`. If you want to change both the instance family and instance type, you can upgrade the major engine version. You can change the instance type to an instance type that belongs to the same instance family or an instance type that belongs to a higher instance family. Special cases exist. The information displayed in the ApsaraDB RDS console shall prevail. The following instance families are sorted in ascending order: share instance family, general-purpose instance family, and dedicated instance family. You cannot downgrade the instance family. For example, you can change the instance family from general-purpose instance family to dedicated instance family. Note If your RDS instance runs RDS High-availability Edition and uses a shared instance type, you cannot directly upgrade the RDS instance to a dedicated instance type on RDS Cluster Edition. If the required instance family is not displayed in the ApsaraDB RDS console, you can create an RDS instance that uses the required instance family and then migrate the data of the original RDS instance to the new RDS instance to upgrade the instance family.
Storage type	You can upgrade the performance levels (PLs) of Enterprise SSDs (ESSDs) for RDS instances that use the ESSD storage type. For example, you can upgrade the storage type from PL1 ESSD to PL2 ESSD. You cannot downgrade PLs of ESSDs. You can upgrade the storage type of an RDS instance that does not run RDS Cluster Edition from standard SSD to ESSD. After the upgrade is complete, you cannot downgrade the storage type from ESSD to standard SSD. Note If your RDS instance runs RDS Cluster Edition, you cannot upgrade the storage type of the RDS instance from standard SSD to ESSD. If you want to upgrade the storage type of the RDS instance, you must create an RDS instance that uses ESSDs and then migrate the data of the original RDS instance to the new RDS instance.
Storage capacity	You can expand the storage capacity of all RDS instances. However, you cannot reduce the storage capacity of an RDS instance. You can expand the storage capacity at a step size of 5 GB. The new storage capacity cannot exceed the maximum storage capacity that is supported by the instance type. Note The storage capacity of a read-only RDS instance cannot be less than the storage capacity of the primary RDS instance to which the read-only RDS instance is attached. If the requirement is not met and you want to expand the storage capacity for the primary and read-only RDS instances, you must increase the storage capacity of the read-only RDS instance before you can increase the storage capacity of the primary RDS instance. If the storage capacity range that is supported by an instance type does not meet your business requirements, we recommend that you select another instance type.

Prerequisites

Your Alibaba Cloud account does not have overdue renewal orders.

Usage notes

After you change the specifications of your RDS instance, you do not need to manually restart the RDS instance.
A specification change may trigger a data migration. After the migration is complete, the system switches over your workloads during the switching time that you specify. The switchover does not interrupt the synchronization of incremental data. During the switchover, a 30-second transient connection may occur, and you cannot perform most of the operations that are related to databases, accounts, and networks on the RDS instance. We recommend that you change the specifications during off-peak hours or make sure that your application is configured to automatically reconnect to your RDS instance.
If your RDS instance runs RDS Basic Edition, no secondary RDS instance is provided as hot standby. In this case, if your RDS instance unexpectedly exits, your database service may be unavailable for a long period of time. If you change the specifications or upgrade the database engine version of your RDS instance, your database service may also be unavailable for a long period of time. If you have high requirements for service availability, we recommend that you do not use RDS Basic Edition.
If a read-only RDS instance is attached to your primary RDS instance and you want to expand the storage capacity, make sure that the storage capacity of the read-only RDS instance is greater than or equal to the storage capacity of the primary RDS instance. If the preceding condition is not met, the storage capacity cannot be expanded. We recommend that you expand the storage capacity of the read-only RDS instance before you expand the storage capacity of the primary RDS instance.

Billing rules

For more information, see Change instance specifications.

Procedure

Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.
In the Configuration Information section of the Basic Information page, click Change Specifications.
In the dialog box that appears, select a specification change method and click Next step. This step is required only when the RDS instance uses the subscription billing method.
You can select one of the following specification change methods:
- Upgrade or Downgrade: After you submit a specification change order, the new specifications immediately take effect. Both specification change methods are supported for subscription RDS instances and pay-as-you-go RDS instances.
- Elastic upgrade: You can upgrade the specifications including CPU cores, memory capacity, and storage capacity of an RDS instance to increase overall database performance. This specification change method is available only to users in a whitelist. When the time that is specified by the Restore Point-in-time parameter arrives, the instance type is automatically restored to the instance type that is used at the point in time before an elastic upgrade is performed. The storage capacity is not restored.
After you submit a specification change order, ApsaraDB RDS synchronizes the data of the RDS instance from the disk to a new RDS instance. Then, ApsaraDB RDS switches the information, such as the ID and endpoints, about the RDS instance over to the new RDS instance based on the specification change method that you select.
Change the specifications of the RDS instance. For more information, see Changable specification items.
Note
- Some RDS for SQL Server instances support storage capacity expansion without data loss. When you change only the ESSD PL (such as from ESSD PL1 to PL2) or expand the storage capacity of an instance that supports this feature, the connection to the instance is not interrupted. In this case, you do not need to configure the switchover time. However, if you change the instance type at the same time, you must configure the switchover time.
- If you do not change the specifications of your RDS instance but the Switching Time parameter is displayed on the Change Specifications page, the storage capacity expansion without data loss feature is not supported for your RDS instance. In this case, you can upgrade the major or minor engine version of your instance. For more information, see Upgrade the major engine version.
Configure the Switching Time parameter.
- Switch Immediately After Data Migration: The specification change triggers a data migration. If you select this option, the system immediately switches over your workloads after the data migration is complete.
- Switch Within Maintenance Window: When the specification change is being applied, a transient connection that lasts approximately 30 seconds may occur, and you cannot perform most of the operations that are related to databases, accounts, and network settings. If you select this option, the system switches over your workloads within the maintenance window that you specify. For more information, see Set the maintenance window of an ApsaraDB RDS for SQL Server instance.
Note
You can expand the storage capacity of specific RDS instances without data loss. In this case, the Switching Time parameter is not displayed on the Change Specifications page, and you do not need to specify the switching time for the RDS instances.
Read and select Terms of Service and click Pay Now. In the dialog box that appears, confirm the instance information before and after the specification change and click Continue to complete the payment.
Warning
- After you submit a specification change order, you cannot cancel the order. Therefore, before you submit a specification change order, we recommend that you evaluate whether the new specifications meet your business requirements.
- After you submit a specification change order, do not perform DDL operations before the specification change is applied.

FAQ

Does the change of the PL of the storage type cause service interruptions?

Some RDS for SQL Server instances support storage capacity expansion without data loss. When you change only the ESSD PL (such as from ESSD PL1 to PL2) or expand the storage capacity of an instance that supports this feature, the connection to the instance is not interrupted. In this case, you do not need to configure the switchover time. However, if you change the instance type at the same time, you must configure the switchover time.
If you do not change the specifications of your RDS instance but the Switching Time parameter is displayed on the Change Specifications page, the storage capacity expansion without data loss feature is not supported for your RDS instance. In this case, you can upgrade the major or minor engine version of your instance. For more information, see Upgrade the major engine version.

Can I change the zone and database engine version of my RDS instance?

If your RDS instance does not run SQL Server 2008 R2, you can call the ModifyDBInstanceSpec operation to upgrade the major engine version or change the region and zone of the instance. You can also upgrade the major engine version of your RDS instance in the ApsaraDB RDS console. For more information, see Upgrade the major engine version.
If your RDS instance runs SQL Server 2008 R2 and uses Premium Local SSDs, you can change the zone of the instance while upgrading the major engine version of the instance in the ApsaraDB RDS console. For more information, see Upgrade an ApsaraDB RDS for SQL Server instance with Premium Local SSDs from SQL Server 2008 R2 to SQL Server 2012 or SQL Server 2016.

Note

You can also change the zone of your RDS instance by migrating it to another zone in the same region. For more information, see Migrate an ApsaraDB RDS for SQL Server instance across zones.

Do I need to migrate the data of my RDS instance to a new RDS instance when I increase the storage capacity of my RDS instance?

No, you do not need to manually migrate the data when you increase the storage capacity of your RDS instance. When you expand the storage capacity, the system checks whether the host on which your RDS instance resides can provide sufficient storage. If the host can provide sufficient storage, the system increases the storage capacity of your RDS instance without requiring you to migrate the data. If the host cannot provide sufficient storage, the system migrates the data to a new RDS instance before the system increases the storage capacity. The new RDS instance must be created on a host that provides sufficient storage.

How long does it take to change the specifications of an RDS instance?

A specification change involves data migration. In approximately 90% of the cases, a specification change is complete within 30 minutes.

If I upgrade the CPU cores, memory, and storage capacity of an RDS instance at the same time, how long does a transient connection last?

The transient connection lasts the same as the transient connection that occurs when you separately upgrade the CPU cores, memory, or storage capacity of your RDS instance. In most cases, the transient connection lasts for a few minutes. When the system switches your workloads, a transient connection may occur, or your RDS instance may be restarted. During the switchover, you cannot perform most of the operations that are related to databases, accounts, and network settings. We recommend that you change the specifications of your RDS instance within the specified maintenance window. For more information, see Changable specification items.

Related operation

Change the instance type and storage capacity of an ApsaraDB RDS instance: ModifyDBInstanceSpec