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Which nodes are participating in Under Replication in HDFS

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Rising Star

Hi,

I had 1 millions of files under replicated in my HDFS cluster for a testing scenario, It replicated successfully but I want to know that Which nodes are participating on this operation ?

Like What is the role of namenode and datanode in this under-replication process ?

1 ACCEPTED SOLUTION

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The ALL are; especially when talking about so many files that were under-replicated. Ultimately, the NN is the one who determines if a file is under-replicated. It is then the NN's job to notify one of the DNs that has a good copy of one of the blocks' replicas to copy it to another DN. NN isn't going to do any of the actual movement of bits -- it will just coordinate the whole effort. Hope this helps!

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2 REPLIES 2

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The ALL are; especially when talking about so many files that were under-replicated. Ultimately, the NN is the one who determines if a file is under-replicated. It is then the NN's job to notify one of the DNs that has a good copy of one of the blocks' replicas to copy it to another DN. NN isn't going to do any of the actual movement of bits -- it will just coordinate the whole effort. Hope this helps!

8766-repl2.png

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