:original_name: admin_guide_000351.html

.. _admin_guide_000351:

Restoring IoTDB Metadata
========================

Scenario
--------

To ensure IoTDB metadata security and prevent the IoTDB service from being unavailable due to IoTDB file damage, IoTDB metadata needs to be backed up. In this way, the system can restore data timely when an exception is reported or an operation does not achieve the expected result, minimizing the impact on services.

System administrators can create an IoTDB restoration task on FusionInsight Manager. Only manual restoration tasks are supported.

.. important::

   -  Data restoration can be performed only when the system version is consistent with that during data backup.
   -  To restore the data when services are normal, manually back up the latest management data first and then restore the data. Otherwise, the IoTDB data that is generated after the data backup and before the data restoration will be lost.
   -  You are advised to restore the metadata of only one component in a restoration task to prevent the stop of a service or instance from affecting the data restoration of other components. If data of multiple components is restored at the same time, data restoration may fail.

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

After the metadata is restored, the data generated after the data backup and before the data restoration is lost.

Procedure
---------

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

#. In the row where the specified backup task is located, choose **More** > **View History** in the **Operation** column to display the historical execution records of the backup task.

   In the window that is displayed, select a success record and click **View** in the **Backup Path** column to view its backup path information and find the following information:

   -  **Backup Object**: indicates the backup data source.

   -  **Backup Path**: indicates the full path where backup files are stored.

      Select the correct path, 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 **Restoration Configuration**, select **IoTDB** under **Metadata and other data**.

   .. note::

      If multiple IoTDB services are installed, select the IoTDB service to be restored.

#. Select a backup directory type for **Path Type**.

   The configurations vary based on backup directory types:

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

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

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

      If you select this option, configure 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 complete 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**.

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

      If you select this option, configure the following parameters:

      -  **Source NameService Name**: indicates the NameService name of the backup data cluster, for example, **hacluster**. You can obtain it from the **NameService Management** page of HDFS of the standby 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 Active NameNode IP Address**: indicates the service plane IP address of the active NameNode in the standby cluster.
      -  **Source Standby NameNode IP Address**: indicates the service plane IP address of the standby NameNode in the standby cluster.
      -  **Source NameNode RPC Port**: indicates the value of **dfs.namenode.rpc.port** in the HDFS basic configuration of the standby cluster.
      -  **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**.

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

      If you select this option, configure 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 complete 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 this option, configure 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 complete 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**.

#. Click **OK**.

#. In the restoration task list, locate the row where the created task is located, and click **Start** in the **Operation** column.

   -  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.

#. Choose **Cluster** > **Services** and start the IoTDB service.
