Cloudera Docs

Enabling HBase META Replicas

When many HBase clients try to access a META table concurrently, it becomes overloaded, which in turn reduces the HBase performance. When you enable HBase META replicas, HBase maintains read-only copies of the META table on additional region servers and ensures that the META table reads are load balanced between the replicas. This improves the HBase performance.

You can enable HBase META replicas by configuring a set of properties in Cloudera Manager.

  1. Open Cloudera Manager and go to the HBase service.
  2. Click the Configuration tab.
  3. Select Scope > (Service-Wide).
  4. Locate the HBase Service Advanced Configuration Snippet (Safety Valve) for hbase-site.xml property or search for it by typing its name in the search box.
  5. Add the following property values:

    • Master Replica Count: hbase.meta.replica.count

      Description: The number of region replicas to maintain for the META table.

      Value: 3

    • Region Locator Mode: hbase.locator.meta.replicas.mode

      Description: The Region Locator's mode when META replica is configured.

      Value: LoadBalance

    • Meta Replicas Use: hbase.meta.replicas.use

      Description: Specifies whether to use META table replicas.

      Value: true

    • Region Replica Replication Catalog Enabled: hbase.region.replica.replication.catalog.enabled

      Description: Specifies whether to enable asynchronous WAL replication for META region replicas.

      Value: true

  6. Select Scope > Gateway.
  7. Locate the HBase Client Advanced Configuration Snippet (Safety Valve) for hbase-site.xml property or search for it by typing its name in the search box.
  8. Add the property values mentioned in Step 5.
  9. Enter a Reason for change, and then click Save Changes .
  10. Restart the role and service when Cloudera Manager prompts you to restart.