The data is in HDFS in case of WordCount MR sample.
In hdfs, you have the metadata in NameNode and actual data as blocks replicated across DataNodes.
In case of reducer, If a reducer is running on a particular node then you have one replica of the blocks in the same node (If there is no space issues) and rest replicas on other nodes.
Sent from remote device, Please excuse typos
From: Raj Hadoop <[EMAIL PROTECTED]>
Date: Tue, 16 Apr 2013 21:49:34
To: [EMAIL PROTECTED]<[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Basic Doubt in Hadoop
I am new to Hadoop. I started reading the standard Wordcount program. I got this basic doubt in Hadoop.
After the Map - Reduce is done, where is the output generated? Does the reducer ouput sit on individual DataNodes ? Please advise.