Hello @OscarData. Running HDFS balancer will not help to balance the disks of a data node. Balancer will only help to balance the data among multiple data nodes but to balance the disks in a particular data node, you would need to run the intra disk balancer. Please review this article on how to run it to balance the disks in a data node. Thanks! ... View more

@Crash The HDFS balancer works based on the DFS used%. By default the threshold is 10%. So if the DFS used % on a particular data node is greater or lesser than 10% of the average DFS used% across all data nodes, then running the balancer will help to balance the nodes, if the DFS used % is not greater or less than 10% of the average DFS used%, then HDFS will consider the data node to be balanced.  ... View more