Hello, I am running compute intensive job using Hadoop Streaming (hadoop version 0.19.1), and my mapper input has several thousand small files. My system has 4 nodes and 8 cores per node.
I want to run 8 mappers per node to use all 8 cores, but whatever the mapred.map.tasks value is, I can see only two mappers per node (when I check it using ps -ef|grep mapper_name). Any suggestions? Thank you very much, -seunghwa