what is rack awareness in hadoop

Rack Awareness in Hadoop 6

Usually Hadoop clusters of more than 30-40 nodes are configured in multiple racks.┬áCommunication between two data nodes on the same rack is efficient than the same between two nodes on different racks. In large clusters of Hadoop, in order to improve network traffic while reading/writing HDFS files, NameNode chooses data nodes which are on the same rack or a near by rack to read/write request (client node). NameNode achieves this […]