Restoring Metadata¶
DDM automatically backs up DDM instance metadata at 02:00 UTC+00:00 every day and retains the backup data for 30 days. Metadata backup is also triggered by key operations that affect metadata, such as deleting a schema, deleting data after shard configuration, and deleting instances.
When you delete a schema by mistake or your RDS for MySQL instances become abnormal, metadata restoration allows you to restore your DDM instance metadata and match the metadata with the RDS instance that has completed PITR to re-establish the relationship between your DDM instance and RDS instance. Metadata restoration supports only RDS for MySQL.
To restore metadata of a DDM instance, you can specify a point in time by referring to Restoring Metadata to a Point in Time, or using an available backup by referring to Restoring Metadata Using an Available Backup.
Precautions¶
Metadata restoration mainly restores the metadata of your DDM instance to a new DDM instance. It starts after a point-in-time recovery (PITR) for the associated data nodes is complete.
Note
PITR indicates that a data node has been restored to a specified point in time.
The destination DDM instance is not associated with any RDS for MySQL instance and has no schemas or accounts.
Ensure that the selected RDS for MySQL instance has completed PITR.
Restoration is not supported if the destination DDM instance is in the primary network and its associated RDS for MySQL instance is in the extended network.
The source DDM instance must be of the version 2.3.2.11 or later, and the destination DDM instance must be of the version 3.0.8 or later.
Time points that data can be restored to depend on the backup policy set on original data nodes.
Restoring Metadata to a Point in Time¶
Log in to the DDM console.
In the DDM instance list, locate the newly-created instance and click its name.
In the navigation pane on the left, choose Backups & Restorations.
Click Restore Metadata.
On the displayed page, specify a time point. DDM will select an appropriate DDM metadata backup closest to the time point.
Table 1 Parameter description¶ Parameter
Description
Restore To
Specify a point in time. DDM will restore metadata to this point in time using the most recent backup.
Destination DDM Instance
Select the DDM instance created in 2 as the destination instance.
Destination Data Nodes
Select the RDS for MySQL instances that have completed PITR. DDM will match the selected data nodes with shard information in the selected metadata backup.
Click OK. If a message is displayed indicating that the metadata is restored successfully, the restoration is complete.
Restoring Metadata Using an Available Backup¶
Log in to the DDM console.
In the navigation pane on the left, choose Backups.
Locate the required backup based on the instance name and backup time and click Restore in the Operation column.
On the displayed page, configure required parameters.
Table 2 Parameter description¶ Parameter
Description
Backup Name
Name of the backup to be restored.
Destination DDM Instance
Select the DDM instance created in 2 as the destination instance.
Destination Data Nodes
Select the RDS for MySQL instances that have completed PITR. DDM will match the selected data nodes with shard information in the selected metadata backup.
Click OK. If a message is displayed indicating that the metadata is restored successfully, the restoration is complete.