Restoring a DB Instance from Backups

Scenarios

This section describes how to use an automated or manual backup to restore a DB instance to the status when the backup was created. The restoration is at the DB instance level.

When you restore a DB instance from a backup file, the backup file is downloaded from OBS and then restored to the DB instance at an average speed of 100 MB/s.

Function Description

**Table 1** Function description
Item	Description
Restoration scope	The entire instance
Instance data after restoration	The instance data after restoration is consistent with that in the full backup file used for the restoration. Restoring data to a new instance creates an instance with the same data as that in the backup file. Restoring data to the original or an existing instance will overwrite the instance data.
Scenario	Restoration to a new instance Restoration to the original instance Restoration to an existing instance other than the original one
Configurations for restoring to a new instance	The DB engine and engine version of the new instance are the same as those of the original instance. The storage space of the new instance is the same as that of the original instance by default and the new instance must be at least as large as the original instance. Other parameters need to be reconfigured.
Time required	The time required depends on how much data there is in the instance. The average restoration speed is 100 MB/s.

Constraints

You can restore to new DB instances from backups only when your account balance is greater than or equal to $0 USD. You will pay for the new instance specifications.
If transparent page compression is enabled by specifying attributes in the CREATE TABLE statement for the original DB instance, the restoration may fail due to insufficient storage space.
Constraints on restoring data to the original DB instance:
- If the DB instance for which the backup is created has been deleted, data cannot be restored to the original DB instance.
- Restoring to the original DB instance will overwrite all existing data and the DB instance will be unavailable during the restoration process.
Constraints on restoring data to an existing DB instance:
- If the target existing DB instance has been deleted, data cannot be restored to it.
- Restoring to an existing DB instance will overwrite data on it and cause the existing DB instance to be unavailable.
- To restore backup data to an existing DB instance, the selected DB instance must use the same DB engine and the same or a later version than the original DB instance.
- Ensure that the storage space of the selected existing DB instance is greater than or equal to the storage space of the original DB instance. Otherwise, data will not be restored.

Supported Storage Types

If you restore data to your original instance, the storage type of the instance does not change. If you restore data to a new instance or an existing instance other than the original one, the storage types supported are listed in Table 2.

**Table 2** Supported storage types
Original Storage Type	Restore To	New Storage Type
Cloud SSD	New instance and existing instance other than the original instance	Cloud SSD
Extreme SSD	New instance and existing instance other than the original instance	Cloud SSD Extreme SSD

Procedure

Log in to the management console.
Click in the upper left corner and select a region.
Click in the upper left corner of the page and choose Databases > Relational Database Service.
On the Backups page, select the backup to be restored and click Restore in the Operation column.

Alternatively, click the target DB instance on the Instances page. On the displayed page, choose Backups & Restorations. On the displayed page, select the backup to be restored and click Restore in the Operation column.
Select a restoration method and click OK.

If you have enabled operation protection, click Send Code in the displayed Identity Verification dialog box and enter the obtained verification code. Then, click OK.

Two-factor authentication improves the security of your account. For details about how to enable operation protection, see Identity and Access Management User Guide.
- Create New Instance
  The Create New Instance page is displayed.
  - The DB engine and engine version of the new instance are the same as those of the original instance.
  - Storage space of the new DB instance is the same as that of the original DB instance by default and the new instance must be at least as large as the original DB instance.
  - Other settings are the same as those of the original DB instance by default and can be modified. For details, see Buy a DB Instance.
  Figure 1 Restoring to a new DB instance
  
  Figure 2 Creating a new instance
- Restore to Original
  1. Select "I acknowledge that after I select Restore to Original, data on the original databases will be overwritten and the original DB instance will be unavailable during the restoration." and click Next.
  2. Confirm the information and click OK.
- Restore to Existing
  1. Select "I acknowledge that restoring to an existing DB instance will overwrite data on the instance and will cause the existing DB instance to be unavailable during the restoration. Only DB instances that can be used as target instances for the restoration are displayed here. Eligible instances must have the same DB engine type, version, and at least as much storage as the instance being restored.
  2. Select an existing instance and click Next.
  3. Confirm the information and click OK.
View the restoration result. The result depends on which restoration method was selected:
- Create New Instance
  
  A new DB instance is created using the backup data. The status of the DB instance changes from Creating to Available.
  
  The new DB instance is independent from the original one. If you need read replicas to offload read pressure, create one or more for the new DB instance.
  
  After the new instance is created, a full backup will be automatically triggered.
- Restore to Original
  On the Instances page, the status of the original DB instance changes from Restoring to Available. If the original DB instance contains read replicas, the read replica status is the same as the original DB instance status.
  
  After the restoration is complete, a full backup will be automatically triggered.
- Restore to Existing
  On the Instances page, the status of the target existing DB instance changes from Restoring to Available. If the target existing DB instance contains read replicas, the read replica status is the same as the target existing DB instance status.
  
  After the restoration is complete, a full backup will be automatically triggered.
  
  You can view the detailed progress and result of the task on the Task Center page. For details, see Task Center.