This topic describes how to enable the snapshot backup feature for an ApsaraDB RDS for SQL Server instance. Snapshot backups are faster than physical backups and support a larger amount of data.

Prerequisites

  • Your RDS instance uses standard SSDs or enhanced SSDs (ESSDs).
  • The cross-region backup feature is disabled for your RDS instance. If this feature is enabled, you must disable this feature before you enable the snapshot backup feature. For more information, see Disable cross-region backups for an RDS instance.
  • 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 is fast. The backup speed varies based on the specifications of your RDS instance. The backup is extremely fast. The speed of creating a snapshot backup is approximately twice the speed of creating a physical backup.
Note The first time you create a snapshot backup, ApsaraDB RDS backs up all 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 as Every 30 Minutes.
Restoration speed The restoration is fast. The restoration speed varies based on the specifications of your RDS instance. The restoration 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 log backup files that are used are generated between the point in time at which the most recent 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 significantly affects 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 backup feature of ApsaraDB RDS for SQL Server is 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 are faster than physical backups.
  • Snapshot backups do not occupy CPU or memory resources. Snapshot backups occupy fewer I/O resources than physical backups. When snapshot backups are being created, the performance of your RDS instance is not significantly affected.
  • Snapshot backups provide faster restoration than physical backups. Snapshot backups reduce recovery time objective (RTO) and improve the fault resistance of your database service.
  • After you enable the snapshot backup feature, 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 fees 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 instance 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 can be used only for full backups. You cannot perform snapshot backups for individual databases or tables.
  • Snapshot backup files cannot be downloaded.

Procedure

By default, an instance uses the Physical Backup method. You can change the backup method to Snapshot Backup.

  1. Access RDS Instances, select a region at the top, and then click the ID of the target RDS instance.
  2. In the left-side navigation pane, click Backup and Restoration.
  3. On the Backup and Restoration page, click the Backup Settings tab. Then, click Edit to the right of Data Backup Settings.
  4. In the dialog box that appears, set the Backup Method parameter to Snapshot Backup and click Save.
    Notice
    • After you set the Backup Method parameter to Snapshot Backup, you cannot change the value of the parameter to Physical Backup.
    • After you change the backup method of your RDS instance to Snapshot Backup, you can still perform a physical backup to back up your RDS instance. For more information, see Manually back up your RDS instance.
    • After you set the Backup Method parameter to Snapshot Backup, the Backup Frequency parameter is automatically set to Every 30 Minutes. You cannot change this value.

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 the 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 binary log files of an ApsaraDB RDS instance.