Backing Up HDFS Service Data

Scenario

To ensure HDFS service data security routinely or before a major operation on HDFS (such as upgrade or migration), you need to back up HDFS service data. The backup data can be used to recover the system if an exception occurs or the operation has not achieved the expected result, minimizing the adverse impacts on services.

You can create a backup task on FusionInsight Manager to back up HDFS service data. Both automatic and manual backup tasks are supported.

Encrypted directories cannot be backed up or restored.

Prerequisites

• To back up data to a remote HDFS, the following conditions must be met:
  • A standby cluster for backing up data has been created. The authentication mode must be the same as that of the active 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 Configuring Mutual Trust Between MRS Clusters. 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 Enabling MRS Inter-Cluster Replication.
  • 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 HDFS in the standby cluster has sufficient space. You are advised to save backup files in a custom directory.

• Backup policies, including the backup task type, period, backup object, backup directory, and Yarn queue required by the backup task are planned based on service requirements.
• On the HDFS client, you have executed the hdfs lsSnapshottableDir command as user hdfs to check the list of directories for which HDFS snapshots have been created in the current cluster and ensured that the HDFS parent directory or subdirectory where data files to be backed up are stored does not have HDFS snapshots. Otherwise, the backup task cannot be created.
• If you want to back up data to NAS, you have deployed the NAS server in advance.

Backing Up HDFS Service Data

1. On FusionInsight Manager, choose O&M > Backup and Restoration > Backup Management.
2. Click Create.
3. Set Name to the name of the backup task.
4. Select the cluster to be operated from Backup Object.
5. Set Mode to the type of the backup task.

   Periodic indicates that the backup task is executed by the system periodically. Manual indicates that the backup task is executed manually.

   Table 1 Periodic backup parameters

   Parameter	Description
   Started	Indicates the time when the task is started for the first time.
   Period	Indicates the task execution interval. The options include Hours and Days.
   Backup Policy	Full backup at the first time and incremental backup subsequently Full backup every time Full backup once every n times NOTE: Incremental backup is not supported when Manager data and component metadata are backed up. Only Full backup every time is supported. If Path Type is set to NFS or CIFS, incremental backup cannot be used. When incremental backup is used for NFS or CIFS backup, the latest full backup data is updated each time the incremental backup is performed. Therefore, no new recovery point is generated.

6. In Configuration, select HDFS.
7. Set Path Type of HDFS to a backup directory type.

   The following backup directory types are supported:

   • RemoteHDFS: indicates that the backup files are stored in the HDFS directory of the standby cluster.
     If you select this option, set the following parameters:

     • Destination NameService Name: indicates the NameService name of the standby cluster. You can set it to the NameService name (haclusterX, haclusterX1, haclusterX2, haclusterX3, or haclusterX4) of the built-in remote cluster of the cluster, or the NameService name of a configured 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.
     • Target NameNode IP Address: indicates the IP address of the NameNode service plane in the standby cluster. It can be of an active or standby node.
     • Target Path: indicates the HDFS directory for storing standby cluster backup data. The storage path cannot be an HDFS hidden directory, such as a snapshot or recycle bin directory, or a default system directory, such as /hbase or /user/hbase/backup.
     • Maximum Number of Backup Copies: indicates the number of backup file sets that can be retained in the backup directory.
     • 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.
     • Maximum Number of Maps: indicates the maximum number of maps in a MapReduce task. The default value is 20.
     • Maximum Bandwidth of a Map (MB/s): indicates the maximum bandwidth of a map. The default value is 100.
     • NameService Name: indicates the NameService name of the backup directory. The default value is hacluster.
   • NFS: indicates that backup files are stored in the NAS using the NFS protocol.
     If you select this option, 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.
     • Maximum Number of Backup Copies: indicates the number of backup file sets that can be retained in the backup directory.
     • Server Shared Path: indicates the configured shared directory of the NAS server. (The shared path of the server cannot be set to the root directory, and the user group and owner group of the shared path must be nobody:nobody.)
     • 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.
     • Maximum Number of Maps: indicates the maximum number of maps in a MapReduce task. The default value is 20.
     • Maximum Bandwidth of a Map (MB/s): indicates the maximum bandwidth of a map. The default value is 100.
     • NameService Name: indicates the NameService name of the backup directory. The default value is hacluster.
   • CIFS: indicates that backup files are stored in the NAS using the CIFS protocol. If you select this option, 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.
     • Maximum Number of Backup Copies: indicates the number of backup file sets that can be retained in the backup directory.
     • Server Shared Path: indicates the configured shared directory of the NAS server. (The shared path of the server cannot be set to the root directory, and the user group and owner group of the shared path must be nobody:nobody.)
     • 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.
     • Maximum Number of Maps: indicates the maximum number of maps in a MapReduce task. The default value is 20.
     • Maximum Bandwidth of a Map (MB/s): indicates the maximum bandwidth of a map. The default value is 100.
     • NameService Name: indicates the NameService name of the backup directory. The default value is hacluster.
   • SFTP: indicates that backup files are stored in the server using the SFTP protocol.
     If you select this option, 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.
     • Server Shared Path: indicates the backup path on the SFTP server.
     • Maximum Number of Backup Copies: indicates the number of backup file sets that can be retained in the backup directory.
     • 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.
     • Maximum Number of Maps: indicates the maximum number of maps in a MapReduce task. The default value is 20.
     • Maximum Bandwidth of a Map (MB/s): indicates the maximum bandwidth of a map. The default value is 100.
     • NameService Name: indicates the NameService name of the backup directory. The default value is hacluster.

8. Set Maximum Number of Recovery Points to the number of snapshots that can be retained in the cluster.
9. Set Backup Content to one or multiple HDFS directories to be backed up based on service requirements.

   You can select backup data using either of the following methods:

   • Adding a backup data file

     Click the name of a database in the navigation pane to show all the tables in the database, and select specified tables.

     MRS 3.2.0 or later:

     1. Click Add.
     2. Select the table to be backed up under File Directory, and click Add to add the table to Backup Content.
     3. Click OK.
   • Selecting using regular expressions
     1. Click Query Regular Expression.
     2. Enter the parent directory full path of the directory in the first text box as prompted. The directory must be the same as the existing directory, for example, /tmp.
     3. Enter a regular expression in the second text box. Standard regular expressions are supported. For example, to get all files or subdirectories in the parent directory, enter ([\s\S]*?). To get files whose names consist of letters and digits, for example, file1, enter file\d*.
     4. Click Refresh to view the displayed directories in Directory Name.
     5. Click Synchronize to save the result.
     

     • When entering regular expressions, click or to add or delete an expression.
     • If the selected table or directory is incorrect, click Clear Selected Node to deselect it.
     • The backup directory cannot contain files that have been written for a long time. Otherwise, the backup task will fail. Therefore, you are not advised to perform operations on the top-level directory, such as /user, /tmp, and /mr-history.

10. Click Verify to check whether the backup task is configured correctly.

    The possible causes of the verification failure are as follows:

    • The target NameNode IP address is incorrect.
    • The queue name is incorrect.
    • The parent directory or subdirectory of the HDFS directory where data files to be backed up are stored has HDFS snapshots.
    • The directory or table to be backed up does not exist.
    • The name of the NameService is incorrect.

11. Click OK.
12. In the Operation column of the created task in the backup task list, click More and select Back Up Now to execute the backup task.

    After the backup task is executed, the system automatically creates a subdirectory for each backup task in the backup directory. The format of the subdirectory name is Backup task name_Data source_Task creation time, and the subdirectory is used to save latest data source backup files. All the backup file sets are stored in the related snapshot directories.