Hi everyone, See HDFS documents, It says "For the common case, when the replication factor is three, HDFS’s placement policy is to put one replica on one node in the local rack, another on a node in a different (remote) rack, and the last on a different node in the same remote rack."
Assume there are two racks A and B. According to rack awareness, the first block is put in rack A, and the the other two replicated blocks will be pushed into rack B. However, why not store the first and second replicas in the local rack (A), and the last in a different remote rack (B)? Both two scenarios have same network traffic. What's the disadvantage of it? Thanks. Best Regards, Jianan
