This topic describes how to enable snapshot backups for an ApsaraDB RDS for SQL Server instance. Compared with physical backups, snapshot backups provide a higher backup speed and allow you to create a larger number of backups.

Prerequisites

  • Your RDS instance uses standard or enhanced SSDs.
  • The cross-region backup feature is not enabled for your RDS instance. If this feature is enabled, you must disable this feature before you enable snapshot backups. For more information, see Disable the cross-region backup feature for an RDS instance.
  • Your RDS instance does not belong to the shared instance family or a dedicated cluster. For more information, see Instance families.
  • Your RDS instance is created after January 1, 2021.

Comparison between snapshot backups and physical backups

Item Physical backup Snapshot backup
Backup speed The backup speed is fast. However, the backup speed varies based on the specifications of your RDS instance. The backup speed is extremely fast. The backup speed of snapshot backups is approximately twice the backup speed of physical backups.
Note When you create a snapshot backup for the first time, ApsaraDB RDS backs up all the data of your RDS instance. This backup process may require a long period of time.
Restoration speed The restoration speed is fast. However, the restoration speed varies based on the specifications of your RDS instance. The restoration speed is extremely fast. The restoration speed is not affected by the amount of data. The restoration speed of snapshot backups is higher than the restoration speed of physical backups.
  • Restore data to a new RDS instance.
    • The time that is required to restore data from a data backup file is approximately 30 minutes. This includes the time that is required to create an RDS instance and the time that is required to restore the data from the data backup file.
    • The time that is required to restore data to a point in time varies based on the volume of logs. This includes the time that is required to create an RDS instance and the time that is required to restore the logs.
  • Restore data to an existing RDS instance
    • The time that is required to restore data from a data backup file is approximately 10 minutes.
    • The time that is required to restore data to a point in time varies based on the volume of logs.
Note The logs that are restored are generated between the point in time at which the closest snapshot backup file is generated and the point in time to which you want to restore data.
Amount of data supported Up to 4 TB of data is supported. Up to 32 TB of data is supported.
Impact on instance performance A large number of resources are occupied. This has a significant impact on the performance of your RDS instance. We recommend that you perform a physical backup during off-peak hours. Only a small number of I/O resources are occupied. This does not significantly affect the performance of your RDS instance. You can perform a snapshot backup at any time.
Download of backup files Physical backup files can be downloaded. Snapshot backup files cannot be downloaded.

Benefits

The data from physical backup files can be restored at a speed of only up to 20 MB per second. Furthermore, each physical backup supports up to 4 TB of data. If you want to restore a large amount of data, the restoration process may require a large amount of time. The snapshot backup feature of ApsaraDB RDS for SQL Server is developed based on Volume Shadow Copy Service, which is provided by Microsoft. This feature allows ApsaraDB RDS to complete a backup within a short period of time. This feature also ensures data consistency and integrity. For more information, see Volume Shadow Copy Service.

Snapshot backups have the following benefits:

  • Snapshot backups each support up to 32 TB of data.
  • Snapshot backups support a higher backup speed than physical backups.
  • Snapshot backups do not occupy CPU or memory resources. Compared with physical backups, snapshot backups occupy less I/O resources. When snapshot backups are being created, the performance of your RDS instance is not significantly affected.
  • Compared with physical backups, snapshot backups provide a higher restoration speed, reduced recovery time objective (RTO), and improved fault resistance for your database service.
  • After you enable snapshot backups, you can still perform physical backups to back up your RDS instance. For more information, see Back up your RDS instance.

Billing

Each RDS instance is allocated a free quota for backup storage. If your usage exceeds the free quota, you are charged for the excess storage. For more information, see Backup storage pricing for an ApsaraDB RDS for SQL Server instance.

Limits

  • Snapshot backup files cannot be stored in a region that is different from the region where your RDS resides. For more information, see Back up an ApsaraDB RDS for SQL Server instance across regions.
  • You can switch your RDS instance from the physical backup method to the snapshot backup method. However, you cannot switch your RDS instance from the snapshot backup method to the physical backup method.
  • The snapshot backup feature supports only full backups. This feature does not support the backups of individual databases and tables.
  • Snapshot backup files cannot be downloaded.

Procedure

By default, the backup method of new RDS instances is physical backup. You can manually switch the RDS instance to the snapshot backup method.

  1. Go to the Backup and Restoration page.
    1. Log on to the RDS management console, click on the left Instances , and then select a region above.
      Select a region
    2. Find your RDS instance and click the ID of the instance. In the left-side navigation pane, click Backup and Restoration.
  2. On the Backup and Restoration page, click the Backup Settings tab. In the Data Backup Settings section, click Edit.
  3. Set the Backup Method parameter to Snapshot Backup and click Save.
    Notice
    • After you switch your RDS instance to the snapshot backup method, you cannot switch your RDS instance to the physical backup method.
    • After you switch your RDS instance to the snapshot backup method, you can still perform physical backups to back up your RDS instance. For more information, see Back up your RDS instance.

What to do next

Back up an ApsaraDB RDS for SQL Server instance

Related operations

Operation Description
Create a backup task Creates a data backup for an ApsaraDB RDS instance.
Query data backup files Queries the data backup files of an ApsaraDB RDS instance.
Query backup settings Queries the backup settings of an ApsaraDB RDS instance.
Modify backup settings Modifies the backup settings of an ApsaraDB RDS instance.
Query backup tasks Queries the backup tasks of an ApsaraDB RDS instance.
Query log backup files Queries the log backup files of an ApsaraDB RDS instance.