distributed-database-middleware/umn/source/backups_and_restorations/restoring_metadata.rst

original_name

ddm_0600017.html

Restoring Metadata

Overview

The metadata backup policy requires DDM to automatically back up DDM instance metadata from 02:00 to 03:00 every day and retain the backup data for 30 days. Metadata backup is also triggered by key operations, such as deleting a schema, deleting source data after shard configuration, and deleting instances.

When you delete a schema by mistake or your RDS for MySQL instance becomes abnormal, metadata restoration allows you to restore your DDM instance metadata and match the metadata with the RDS instance that has PITR completed to re-establish the relationship between your DDM instance and RDS instance. The 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 <ddm_0600017__section128315484524>, or using an available backup by referring to Restoring Metadata Using an Available Backup <ddm_0600017__section132806221525>.

Constraints

• The destination DDM instance is not associated with any RDS for MySQL instance and has no schemas and accounts.
• Ensure that the selected RDS for MySQL instance has PITR completed.
• Restoration is not supported if the DDM instance is in the primary network and the destination 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.

Prerequisites

• You have logged in to the DDM console.
• The target DDM instance is available and running normally.

Restoring Metadata to a Point in Time

1. Create a DDM instance. For details, see Creating a DDM Instance <ddm_06_00017>.

2. In the DDM instance list, locate the newly-created instance and click its name.
3. In the navigation pane on the left, choose Backups & Restorations. Click Restore Metadata.
4. Specify a time point. DDM will select an appropriate DDM metadata backup closest to the time point.
5. Select the destination instance created in 1 <ddm_0600017__li4793191882712>. If there are no instances available, create an instance by referring to Creating a DDM Instance <ddm_06_00017>.
6. Select the RDS for MySQL instance that has PITR completed and click OK.
7. Check for a message that indicates the request is submitted.

Restoring Metadata Using an Available Backup

1. Create a DDM instance. For details, see Creating a DDM Instance <ddm_06_00017>.
2. Switch back to the homepage of the DDM console.
3. In the navigation pane on the left, choose Backups.
4. Locate the required backup based on the instance name and backup time and click Restore in the Operation column.
5. Select the destination instance created in 1 <ddm_0600017__li4793191882712>. If there are no instances available, create an instance by referring to Creating a DDM Instance <ddm_06_00017>.
6. Select the target data node and click OK.
7. Check for a message that indicates the request is submitted.