Help Center/ MapReduce Service/ User Guide (ME-Abu Dhabi Region)/ Managing an Existing Cluster/ Backup and Restoration/ Backing Up Metadata
Updated on 2022-02-22 GMT+08:00
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Backing Up Metadata

Scenario

To ensure metadata security or before and after a critical operation (such as scale-out/scale-in, patch installation, upgrade, or migration) on the metadata, you need to back up the metadata. The backup data can be used to recover the system in time if an exception occurs or the operation has not achieved the expected result, minimizing the adverse impact on services. Metadata includes data of OMS, LdapServer, DBService, and NameNode. MRS Manager data to be backed up includes OMS data and LdapServer data.

By default, metadata backup is supported by the default task. This section describes how to create a backup task and back up metadata on MRS. You can back up data both automatically or manually.

Prerequisites

  • A standby cluster for backing up data has been created, and the network is normal. For the security group of each cluster, you need to add inbound rules of the security group of the peer cluster to allow access requests from all ECSs in the security group using all protocols and ports.
  • The backup type, period, policy, and other specifications have been planned based on the service requirements and you have checked whether Data storage path/LocalBackup/ has sufficient space on the active and standby management nodes.
  • You have synchronized IAM users (on the Dashboard tab page, click Click to synchronize on the right side of IAM User Sync to synchronize IAM users).

Procedure

  1. Create a backup task.

    1. On the cluster details page, click Backups & Restorations.

      For MRS 3.x, see Backing Up Data.

    2. On the Backups tab page, click Create Backup Task.

  2. Configure a backup policy.

    1. Set Task Name to the name of the backup task.
    2. Set Backup Mode to the type of the backup task. Periodic indicates that the backup task is periodically executed and Manual indicates that the backup task is manually executed.

      To create a periodic backup task, set the following parameters:

      • Started: indicates the time when the task is started for the first time.
      • Period: indicates the task execution interval. The options include By hour and By day.
      • Backup Policy: indicates the volume of data to be backed up in each task execution. Supports Full backup at the first time and incremental backup later, Full backup every time, and Full backup once every n times. If you select Full backup once every n times, you need to specify the value of n.

  3. Select backup sources.

    In the Configuration area, select the metadata type, such as OMS and LdapServer.

  4. Set backup parameters.

    1. Set Path Type of OMS and LdapServer to the backup directory type.

      The following backup directory types are supported:

      • LocalDir: indicates that the backup files are stored on the local disk of the active management node and the standby management node automatically synchronizes the backup files. By default, the backup files are stored in Data storage path/LocalBackup/. If you select LocalDir, you need to set the maximum number of copies to specify the number of backup files that can be retained in the backup directory.
      • LocalHDFS: indicates that the backup files are stored in the HDFS directory of the current cluster. If you select LocalHDFS, set the following parameters:
        • Target Path: indicates the HDFS directory for storing the backup files. The save path cannot be an HDFS hidden directory, such as a snapshot or recycle bin directory, or a default system directory.
        • Max Number of Backup Copies: indicates the number of backup files that can be retained in the backup directory.
        • Target Instance Name: indicates the NameService name of the backup directory. The default value is hacluster.
    2. Click OK.

  5. Execute a backup task. In the Operation column of the created task in the backup task list, perform the following operations:

    • If Backup Type is set to Periodic, click Back Up Now.
    • If Backup Type is set to Manual, click Start to start 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_Task creation time, and the subdirectory is used to save data source backup files. The format of the backup file name is Version_Data source_Task execution time.tar.gz.

Parent topic: Backup and Restoration