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    ApsaraDB RDS:Change instance specifications

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    ApsaraDB RDS:Change instance specifications

    Last Updated:Dec 17, 2024

    This topic describes how to change the specifications of an ApsaraDB RDS for PostgreSQL instance. The specifications include the RDS edition, instance type, and storage capacity.

    Prerequisites

    • The billing method of your RDS for PostgreSQL instance is subscription or pay-as-you-go.

      Note

      To change the specifications of a Serverless RDS for PostgreSQL instance, see Serverless ApsaraDB RDS for PostgreSQL instances.

    • Your RDS for PostgreSQL instance is in the Running state.

    • Your Alibaba Cloud account does not have overdue renewal orders.

    Configuration items

    You can create read-only RDS instances to offload read requests from a primary RDS instance in your database system. This way, the read capability of your database system is increased. For more information, see Overview of read-only ApsaraDB RDS for PostgreSQL instances and Create a read-only ApsaraDB RDS for PostgreSQL instance.

    Warning

    When you change the specifications of your RDS instance, a transient connection or instance restart may occur during the workload switchover. You cannot perform most operations that are related to databases, accounts, and network settings during the switchover. We recommend that you change the specifications of your RDS instance within the maintenance window. For more information, see Configure a maintenance window.

    Configuration item

    Description

    Impact

    RDS edition

    You can upgrade an RDS instance from RDS Basic Edition to RDS High-availability Edition. For more information, see Upgrade an ApsaraDB RDS for PostgreSQL instance from Basic Edition to High-availability Edition.

    A transient connection occurs.

    Product type

    You can change the product type of your RDS instance between YiTian and standard. For more information about the differences between YiTian and standard instances, see Product types.

    Note

    • If you cannot select the required product type when you change the specifications of the RDS instance, no resources are available in the zone in which the RDS instance resides.

      You can go to the ApsaraDB RDS buy page to view the zones that support the required product type, migrate the RDS instance to a zone that can provide the required resources, and then change the product type. For more information, see Migrate an ApsaraDB RDS for PostgreSQL instance across zones in the same region.

    • If you want to change the product type of an RDS instance, make sure that the minor engine version of the RDS instance after the change is later than or the same as the current minor engine version. If the minor engine version after the change is earlier than the current minor engine version, the product type change fails.

    • YiTian RDS instances do not support the plv8, rdkit, and madlib extensions. When you change the product type from standard to YiTian, make sure that these extensions are not used. For more information about the extensions supported by each product type, see Extensions supported by ApsaraDB RDS for PostgreSQL.

    A transient connection occurs.

    Storage type

    You can change the storage type of your RDS instance.

    • If your RDS instance uses cloud disks, take note of the following points:

      • You can upgrade the storage type of your RDS instance from standard SSD to Enterprise SSD (ESSD). ESSDs support the following performance levels (PLs): PL1, PL2, and PL3. You cannot downgrade the storage type of your RDS instance from ESSD to standard SSD.

      • You can upgrade or downgrade the ESSD storage type of your RDS instance between ESSD PL1, ESSD PL2, and ESSD PL3.

    • If your RDS instance uses local SSDs, you cannot change the storage type of the RDS instance.

    Note

    For more information about the performance differences among different storage types, see Storage types.

    • If you upgrade or downgrade the ESSD storage type of your RDS instance between ESSD PL1, ESSD PL2, and ESSD PL3, no transient connections occur.

    • If you upgrade the storage type of your RDS instance from standard SSD to ESSD, a transient connection occurs.

    Instance type

    You can change the instance type of your RDS instance.

    Note

    • If you upgrade the instance type of your RDS instance, a transient connection occurs.

    • If you downgrade the instance type of your RDS instance, the primary RDS instance is restarted. After the primary RDS instance is restarted, a transient connection occurs.

    • When you change the instance type of your RDS instance, make sure that specific kernel parameters of the read-only RDS instance are consistent with those of the primary RDS instance. If you change the kernel parameters of the read-only RDS instance, the read-only RDS instance is restarted and a transient connection occurs.

    Storage capacity

    You can expand or reduce the storage capacity of your RDS instance.

    • Storage capacity expansion: You can expand the storage capacity of your RDS instance at a step size of 5 GB. The new storage capacity of your RDS instance cannot exceed the maximum storage capacity that is supported by the instance type of the RDS instance. For more information, see Primary ApsaraDB RDS instance types.

    • Storage capacity reduction: You can reduce the storage capacity of your RDS instance that uses cloud disks without the need to change the RDS edition or architecture of the RDS instance. The new storage capacity of your RDS instance must be greater than or equal to the minimum storage capacity that is supported by the instance type of the RDS instance. You can use the following formula to calculate the minimum storage capacity to which you can reduce your RDS instance: min{Used storage × 1.3, Used storage + 400 GB}. You can reduce the storage capacity at a step size of 5 GB. For more information, see Reduce the storage capacity of an ApsaraDB RDS for PostgreSQL instance that uses cloud disks.

      Example

      Your RDS instance uses a PL1 ESSD that provides 2,000 GB of storage capacity. The minimum storage capacity that is supported by the instance type of the RDS instance is 20 GB.

      • If 10 GB of storage is used, the value calculated by using the preceding formula is 13 GB. In this case, the minimum storage capacity to which you can reduce your RDS instance is 20 GB.

      • If 500 GB of storage is used, the value calculated by using the preceding formula is 650 GB. In this case, the minimum storage capacity to which you can reduce your RDS instance is 650 GB.

      • If 1,500 GB of storage is used, the value calculated by using the preceding formula is 1,900 GB. In this case, the minimum storage capacity to which you can reduce your RDS instance is 1,900 GB.

    Note

    • If your RDS instance uses local disks, we recommend that you use the major version upgrade feature to upgrade the RDS instance to an instance that runs a later database engine version and uses cloud disks. You can reduce the storage capacity of your RDS instance when you upgrade the major engine version. For more information, see Upgrade the major engine version.

    • If your RDS instance is created before October 10, 2022 and uses an original architecture, you must update the minor engine version to the latest version and then reduce the storage capacity of the RDS instance. For more information, see Update the minor engine version.

    • You can manually change the specifications of your RDS instance that uses cloud disks to adjust the storage capacity. You can also enable the automatic storage expansion feature for your RDS instance. After the feature is enabled, the system automatically expands the storage capacity to ensure stable service operations when the percentage of the remaining storage reaches the specified threshold. For more information, see Configure automatic storage expansion for an ApsaraDB RDS for PostgreSQL instance.

    • If the RDS instance is being backed up, you can start a storage capacity expansion task after the backup is complete. We recommend that you expand the storage capacity of the RDS instance at the point in time other than the backup time.

    • If the primary RDS instance uses cloud disks, take note of the following points:

      • No transient connections occur during the storage capacity expansion.

      • Transient connections occur during the storage capacity reduction.

    • If your RDS instance uses local disks, a transient connection occurs.

    Billing rules

    For more information, see Specification change fees.

    Usage notes

    • 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.

      Note

      Whether a transient connection occurs during a specification change varies based on the configuration items that you want to change. For more information, see the Impact column in the "Configuration items" section of Change the specifications of an ApsaraDB RDS for PostgreSQL instance.

    • When you change the specifications of your RDS instance, a transient connection or instance restart may occur during the workload switchover. You cannot perform most of the operations that are related to databases, accounts, and network settings during the switchover. We recommend that you change the specifications of your RDS instance within the maintenance window. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance. For more information about the impacts of configuration items, see the Impact column in the "Configuration items" section of Change the specifications of an ApsaraDB RDS for PostgreSQL instance.

    • After you change the specifications of your RDS instance, the ID and endpoints of the RDS instance remain unchanged.

    • After you change the specifications of your RDS instance, you do not need to manually restart the instance.

    • 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 that of the primary RDS instance. Otherwise, the storage capacity cannot be expanded. In this case, 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.

    • When you upgrade the instance type of your RDS instance, make sure that the vSwitch to which the RDS instance is connected has at least two available IP addresses. If the vSwitch does not have sufficient available IP addresses, the instance type upgrade fails. You can log on to the Virtual Private Cloud (VPC) console to check the number of available IP addresses of the vSwitch. If the vSwitch does not have sufficient available IP addresses, switch your RDS instance to a different vSwitch that can provide sufficient available IP addresses before you upgrade the instance type. For more information, see Switch an ApsaraDB RDS for PostgreSQL instance to a different vSwitch.

    Procedure

    1. 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.

    2. In the Configuration Information section of the Basic Information page, click Change Specifications.

    3. In the dialog box that appears, select a specification change method and click Next step. This step is required only for subscription RDS instances.

      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.

      After you submit a specification change order, the system synchronizes the data of the RDS instance from the disk to a new RDS instance. Then, the system 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.

      Warning

      If you select Downgrade, the primary RDS instance is restarted during the switchover. We recommend that you change the specifications of the RDS instance within the maintenance window. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance

    4. Change the specifications of the RDS instance. For more information about the configuration items whose settings can be changed, see Change the specifications of an ApsaraDB RDS for PostgreSQL instance.

    5. Configure the Switching Time parameter.

      • Execute Immediately: The specification change triggers a data migration to a new RDS instance. If you select this option, the system immediately applies the specification change and switches your workloads over to the new RDS instance after the migration process is complete.

      • Switch Within Maintenance Window: When the specification change is being applied, a transient connection or instance restart 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 workloads are switched during the maintenance window that you specify. For more information, see Set the maintenance window of an ApsaraDB RDS for PostgreSQL instance.

      Note

      • If your RDS instance uses cloud disks and you only expand the storage capacity or change the ESSD storage type between different PLs, your workloads are not affected. The system immediately switch over your workloads. In this case, you do not need to select Switch Within Maintenance Window.

      • If your RDS instance uses local disks, we recommend that you select Switch Within Maintenance Window. If the host on which your RDS instance resides can provide sufficient storage resources for storage capacity expansion, the system immediately switch over your workloads, and your workloads are not affected. If the host on which your RDS instance resides cannot provide sufficient storage resources for storage capacity expansion, the system migrates the data of your RDS instance to a new RDS instance. After the migration is complete, the system switches over your workloads to the new RDS instance during the maintenance window. Incremental synchronization is performed during the switchover.

    6. 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

    • How do I change the storage type of my RDS instance from cloud disk to local disk?

      For more information, see How do I change the storage type of an ApsaraDB RDS instance from cloud disk to local disk?

    • If I want to expand only the storage capacity of my RDS instance, do I need to migrate the data of my RDS instance to a new RDS instance?

      • If your RDS instance uses cloud disks, you do not need to migrate the data of the RDS instance to a new RDS instance.

      • If your RDS instance uses local disks, you must check storage resources of the host on which your RDS instance resides.

        • If the host can provide sufficient storage resources, you do not need to migrate the data.

        • If the host cannot provide sufficient storage resources, you need to migrate the data to another host that can provide sufficient storage resources.

    • How do I reduce the storage capacity of my RDS instance?

    • 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 an 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 about the impacts of different configuration items, see Configuration items.

    Related operations

    Operation

    Description

    ModifyDBInstanceSpec

    Changes the specifications of an instance.