:original_name: admin_guide_000217.html

.. _admin_guide_000217:

Restoring DBService data
========================

Scenario
--------

DBService data needs to be recovered in the following scenarios: data is modified or deleted unexpectedly and needs to be restored. After an administrator performs critical data adjustment in DBService, an exception occurs or the operation has not achieved the expected result. All modules are faulty and become unavailable. Data is migrated to a new cluster.

System administrators can create a recovery task in FusionInsight Manager to recover DBService data. Only manual restoration tasks are supported.

.. important::

   -  Data restoration can be performed only when the system version is consistent with that of data backup.
   -  To recover data when the service is running properly, you are advised to manually back up the latest management data before recovering data. Otherwise, the DBService data that is generated after the data backup and before the data recovery will be lost.
   -  By default, MRS clusters use DBServices to store metadata of Hive, Hue, Loader, Spark, and Oozie. Restoring DBService data will restore the metadata of all these components.

Impact on the System
--------------------

-  After the data is restored, the data generated after the data backup and before the data restoration is lost.
-  After the data is restored, the configurations of the components that depend on DBService may expire and these components need to be restarted.

Prerequisites
-------------

-  To restore data from a remote HDFS, you need to prepare a standby cluster. If the active cluster is deployed in security mode and the active and standby clusters are not managed by the same FusionInsight Manager, mutual trust has been configured. For details, see :ref:`Configuring Cross-Manager Mutual Trust Between Clusters <admin_guide_000177>`. If the active cluster is deployed in normal mode, no mutual trust is required.
-  Cross-cluster replication has been configured for the active and standby clusters. For details, see :ref:`Enabling Cross-Cluster Replication <admin_guide_000200>`.
-  Time is consistent between the active and standby clusters and the NTP services on the active and standby clusters use the same time source.

-  The status of the active and standby DBService instances is normal. If the status is abnormal, data restoration cannot be performed.

Procedure
---------

#. On FusionInsight Manager, choose **O&M** > **Backup and Restoration** > **Backup Management**.

#. In the **Operation** column of a specified task in the task list, choose **More** > **View History** to view the historical backup task execution records.

   In the displayed window, locate a specified success record and click **View** in the **Backup Path** column to view the backup path information of the task and find the following information:

   -  **Backup Object** specifies the data source of the backup data.

   -  **Backup Path** specifies the full path where the backup files are saved.

      Select the correct item, and manually copy the full path of backup files in **Backup Path**.

#. On FusionInsight Manager, choose **O&M** > **Backup and Restoration** > **Restoration Management**.

#. Click **Create**.

#. Set **Task Name** to the name of the restoration task.

#. Select the cluster to be operated from **Recovery Object**.

#. In the **Restoration Configuration** area, select **DBService**.

   .. note::

      If multiple DBServices are installed, select the DBServices to be restored.

#. Set **Path Type** of **DBService** to a backup directory type.

   The settings vary according to backup directory types:

   -  **LocalDir**: indicates that the backup files are stored on the local disk of the active management node.

      If you select **LocalDir**, you also need to set **Source Path** to select the backup file to be restored, for example, *Version_Data source_Task execution time*\ **.tar.gz**.

   -  **LocalHDFS**: indicates that the backup files are stored in the HDFS directory of the current cluster.

      If you select **LocalHDFS**, set the following parameters:

      -  **Source Path**: indicates the full path of the backup file in the HDFS, for example, *Backup path/Backup task name_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.
      -  **Source NameService Name**: indicates the NameService name that corresponds to the backup directory when a restoration task is executed. The default value is **hacluster**.

   -  **RemoteHDFS**: indicates that the backup files are stored in the HDFS directory of the standby cluster.

      If you select **RemoteHDFS**, set the following parameters:

      -  **Source NameService Name**: indicates the NameService name of the backup data cluster. You can enter the built-in NameService name of the remote cluster, for example, **haclusterX**, **haclusterX1**, **haclusterX2**, **haclusterX3**, or **haclusterX4**. You can also enter a configured NameService name of the remote cluster.
      -  **IP Mode**: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, **IPv4** or **IPv6**.
      -  **Source NameNode IP Address**: indicates the NameNode service plane IP address of the standby cluster, supporting the active node or standby node.
      -  **Source Path**: indicates the full path of HDFS directory for storing backup data of the standby cluster, for example, *Backup path/Backup task name_Data source_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.
      -  **Queue Name**: indicates the name of the Yarn queue used for backup task execution. The name must be the same as the name of the queue that is running properly in the cluster.

   -  **NFS**: indicates that backup files are stored in the NAS using the NFS protocol.

      If you select **NFS**, set the following parameters:

      -  **IP Mode**: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, **IPv4** or **IPv6**.

      -  **Server IP Address**: indicates the IP address of the NAS server.
      -  **Source Path**: indicates the full path of the backup file on the NAS server, for example, *Backup path/Backup task name_Data source_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.

   -  **CIFS**: indicates that backup files are stored in the NAS using the CIFS protocol.

      If you select **CIFS**, set the following parameters:

      -  **IP Mode**: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, **IPv4** or **IPv6**.

      -  **Server IP Address**: indicates the IP address of the NAS server.
      -  **Port**: indicates the port number used to connect to the NAS server over the CIFS protocol. The default value is **445**.
      -  **Username**: indicates the username set when the CIFS protocol is configured.
      -  **Password**: indicates the password set when the CIFS protocol is configured.
      -  **Source Path**: indicates the full path of the backup file on the NAS server, for example, *Backup path/Backup task name_Data source_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.

   -  **SFTP**: indicates that backup files are stored in the server using the SFTP protocol.

      If you select **SFTP**, set the following parameters:

      -  **IP Mode**: indicates the mode of the target IP address. The system automatically selects the IP address mode based on the cluster network type, for example, **IPv4** or **IPv6**.

      -  **Server IP Address**: indicates the IP address of the server where the backup data is stored.
      -  **Port**: indicates the port number used to connect to the backup server over the SFTP protocol. The default value is **22**.
      -  **Username**: indicates the username for connecting to the server using the SFTP protocol.
      -  **Password**: indicates the password for connecting to the server using the SFTP protocol.
      -  **Source Path**: indicates the full path of the backup file on the backup server, for example, *Backup path/Backup task name_Data source_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.

   -  **OBS**: indicates that backup files are stored in OBS.

      If you select **OBS**, set the following parameters:

      -  **Source Path**: indicates the full OBS path of a backup file, for example, *Backup path/Backup task name_Data source_Task creation time/Version_Data source_Task execution time*\ **.tar.gz**.

         .. note::

            Only MRS 3.1.0 or later supports saving backup files in OBS.

#. Click **OK**.

#. In the restoration task list, locate a created task and click **Start** in the **Operation** column to execute the restoration task.

   -  After the restoration is successful, the progress bar is in green.
   -  After the restoration is successful, the restoration task cannot be executed again.
   -  If the restoration task fails during the first execution, rectify the fault and click **Retry** to execute the task again.
