About the HDFS_READ/WRITE blocks from namenode to datanode

[Li Shengmei]

Hi, all

         I read the namenode.log and found there are HDFS_READ/WRITE
operations from namenode to datanode. That is to say, the datanodes read
blocks from namenode. I want to know what kind of blocks that the datanodes
read from namenode? Should the blocks stored in datanodes, shouldn't that? 

 

Thanks

May