You are correct, map outputs are stored in LFS not in HDFS. Regards Bejoy KS
Sent from remote device, Please excuse typos -----Original Message----- From: Ramesh R Nair <rameshrkco...@gmail.com> Date: Wed, 17 Apr 2013 13:06:32 To: <user@hadoop.apache.org>; <bejoy.had...@gmail.com> Subject: Re: Basic Doubt in Hadoop Hi Bejoy, Regarding the output of Map phase, does Hadoop store it in local fs or in HDFS. I believe it is in the former. Correct me if I am wrong. Regards Ramesh On Wed, Apr 17, 2013 at 10:30 AM, <bejoy.had...@gmail.com> wrote: > 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. > Regards > Bejoy KS > > Sent from remote device, Please excuse typos > ------------------------------ > *From: * Raj Hadoop <hadoop...@yahoo.com> > *Date: *Tue, 16 Apr 2013 21:49:34 -0700 (PDT) > *To: *user@hadoop.apache.org<user@hadoop.apache.org> > *ReplyTo: * user@hadoop.apache.org > *Subject: *Basic Doubt in Hadoop > > Hi, > > 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. > > > Thanks, > Raj >
