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Remove all existing datanodes and copy that data to new added nodes in the cluster

I thought decommissioning all of them would automatically copy data to commissioned nodes. That did not happen though. I currently have 4 DN's in the cluster. I need to remove all 4 of them add 3 new ones instead. I need to maintain the data ofcourse.

What's the way forward?


Super Collaborator

Hi @Simran Kaur,

This may not be perfect answer for you but still you can try this if you want:

stop one of the datanode in cluster and add new data node. rebalance the blocks by using hdfs rebalancer. decommission the stopped data node in cluster. repeat the same process until all data nodes will be added by cluster.

Right but that would not ensure all of the data off the decomissioned nodes and to the live nodes. right?

I did try to rebalance. did not copy data to new ones

Super Collaborator

once you decommissioned one of the data node the data blocks of this node automatically distributed to other nodes.

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