question Re: hdfs balancer is not working in Support Questions

hdfs balancer is not working

irshan — Wed, 31 Jan 2024 07:01:11 GMT

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

Re: hdfs balancer is not working

VidyaSargur — Wed, 31 Jan 2024 07:05:17 GMT

@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.

Re: hdfs balancer is not working

9een — Sun, 04 Feb 2024 18:14:03 GMT

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

Re: hdfs balancer is not working

mike_bronson7 — Sun, 04 Feb 2024 18:59:00 GMT

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

Re: hdfs balancer is not working

irshan — Wed, 07 Feb 2024 09:13:30 GMT

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.

Re: hdfs balancer is not working

sathishkr — Thu, 12 Dec 2024 18:08:58 GMT

@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.