Hey there, I have a doubt about reduce tasks and block writes. Do a reduce task always first write to hdfs in the node where they it is placed? (and then these blocks would be replicated to other nodes) In case yes, if I have a cluster of 5 nodes, 4 of them run DN and TT and one (node A) just run DN, when running MR jobs, map tasks would never read from node A? This would be because maps have data locality and if the reduce tasks write first to the node where they live, one replica of the block would always be in a node that has a TT. Node A would just contain blocks created from replication by the framework as no reduce task would write there directly. Is this correct? Thanks in advance
-- View this message in context: http://lucene.472066.n3.nabble.com/doubt-about-reduce-tasks-and-block-writes-tp4003185.html Sent from the Hadoop lucene-users mailing list archive at Nabble.com.
