hdfs block protocol

[#1]

Hello,

When NN writes data(block) to DN or when DN send block over to next DN, what protocol they use? RPC or HTTP?

[#2 · Accepted solution]

@Mokkan Mok NN does not write blocks to DN, only client to DN and DN to DN (depending on replication factor). Client to DN depends on client you are using. If you are using webhdfs you will be using HTTP for example. Other clients like hdfs use RPC protocol. I think DN to DN replication is always RPC.

HTH

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