This topic describes how to enable snapshot backups for an ApsaraDB RDS for SQL Server instance. Compared with physical backups, snapshot backups support a higher backup speed and a larger amount of data.

Prerequisites

  • Your RDS instance uses standard SSDs or enhanced SSDs (ESSDs).
  • 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 restoration speed varies based on the specifications of your RDS instance. The backup speed is extremely fast. The speed of creating a snapshot backup is approximately twice the speed of creating a physical backup.
Note When you create a snapshot backup for the first time, ApsaraDB RDS backs up all the data of your RDS instance. The backup process may require a long period of time.
Backup frequency Physical backups support the following two backup frequencies:
  • Same as Data Backup
  • Every 30 minutes
The Backup Frequency is fixed to Every 30 minutes and cannot be changed.
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 speed of restoring data from a snapshot backup is higher than the speed of restoring data from a physical backup.
  • 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 log backup file that is used. This includes the time that is required to create an RDS instance and the time that is required to restore the data from the log backup file.
  • 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 log backup file that is used.
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 16 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. 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 long period of time. The snapshot backups of ApsaraDB RDS for SQL Server are developed based on Volume Shadow Copy Service, which is provided by Microsoft. ApsaraDB RDS can complete a snapshot backup within a short period of time. Snapshot backups help ensure data consistency and integrity. For more information, see Volume Shadow Copy Service.

Snapshot backups have the following benefits:

  • Each snapshot backup supports up to 16 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 support 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 Manually 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 Enable cross-region backups for an ApsaraDB RDS for SQL Server instance.
  • You can change the backup method of your RDS instance from Physical Backup to Snapshot Backup. However, you cannot change the backup method of your RDS instance from Snapshot Backup to Physical Backup.
  • Snapshot backups support only full backups. Snapshot backups do not support individual databases or tables.
  • Snapshot backup files cannot be downloaded.

Procedure

By default, the Physical Backup method is enabled for new RDS instances. You can manually change the backup method of an RDS instance to Snapshot Backup.

  1. Visit the RDS instance list, select a region above, and click the target instance ID.
  2. In the left-side navigation pane, click Backup and Restoration.
  3. On the Backup and Restoration page, click the Backup Settings tab and click Edit next to Backup Settings.
  4. Set the Backup Method parameter to Snapshot Backup and click Save.
    Notice
    • After you change the backup method of the RDS instance to Snapshot Backup, you cannot change the billing method of the RDS instance back to Physical Backup.
    • After you change the backup method of the RDS instance to Snapshot Backup, you can still perform Physical Backup to back up your RDS instance. For more information, see Manually back up your RDS instance.
    • If you select the Snapshot Backup method, the backup frequency is fixed to Every 30 Minutes and cannot be changed.

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.