This is the documentation for Cloudera Manager 5.0.x. Documentation for other versions is available at Cloudera Documentation.

Running the Balancer

HDFS data might not always be placed uniformly across DataNodes. One common reason is addition of new DataNodes to an existing cluster. Due to multiple competing considerations, data might not be uniformly placed across the DataNodes. HDFS provides a balancer utility that analyzes block placement and balances data across the DataNodes.

In Cloudera Manager, the HDFS balancer utility is implemented by the Balancer role. The Balancer role usually shows a status of None on the HDFS Status tab because it does not run continuously. To run the HDFS balancer:
  1. Ensure that the HDFS service has a Balancer role.
  2. Go to the HDFS service.
  3. Select Actions > Rebalance.
  4. Click Rebalance that appears in the next screen to confirm. If you see a Finished status, the Balancer ran successfully.
Page generated September 3, 2015.