hdfs balancer is not working

[#1]

Hi Team,

We have 2 nodes cluster, second node we added recently, now we ran hdfs balancer but output is showing the cluster is already balanced but in actual the data is not balanced. Please suggest here..

Thanks

Irshankhan

[#2]

@irshan Welcome to our community! To help you get the best possible answer, I have tagged our HDFS experts @Asok @rki_  who may be able to assist you further.

Please feel free to provide any additional information or details about your query, and we hope that you will find a satisfactory solution to your question.

[#3]

Kindly check if the new Datanode and existing DN node part of same rack

Share below command output 

1. HDFS dfsadmin -report 

2. HDFS dfsadmin -printTopology

[#4]

you can balance the data-node disks usage by decommission and recommission , but if you have only 2 data-nodes then its a problem  better to do it at least 3 data-nodes in cluster 

[#5]

hi,
when we add balancer role then in instance tab its showing N/A. I think its not starting as expected. We are using cloudera express version. its a production cluster. 

[#6]

@irshan When you add balancer as a role in the HDFS cluster, it indeed will show as not started. So its an expected one. Coming to your main query, it could be possible that when you run the balancer, the balancer threshold could be with in the default percentage of 10, so it won't move the blocks. You may have to reduce the balance threshold and try again.