If I am correct : For setting mappers/node --- mapred.tasktracker.map.tasks.maximum For setting reducers/node --- mapred.tasktracker.reduce.tasks.maximum
For setting mappers/job ---- mapred.map.tasks (applicable for whole cluster) For setting reducers/job ---- mapred.reduce.tasks(same) You can change these values in your M/R code using Job / configurattion object Thanks, Praveenesh On Wed, Feb 22, 2012 at 5:08 PM, sangroya <sangroyaa...@gmail.com> wrote: > Hello, > > Could someone please help me to understand these configuration parameters > in > depth. > > mapred.map.tasks and mapred.reduce.tasks > > It is mentioned that default value of these parameters is 2 and 1. > > *What does it mean?* > > Does it mean 2 maps and 1 reduce per node. > > Does it mean 2 maps and 1 reduce in total (for the cluster). Or > > Does it mean 2 maps and 1 reduce per Job. > > Can we change maps and reduce for default example Jobs such as Wordcount > etc. too? > > At the same time, I believe that total number of maps are dependent upon > input data size? > > > Please help me understand these two parameters clearly. > > Thanks in advance, > Amit > > ----- > Sangroya > -- > View this message in context: > http://lucene.472066.n3.nabble.com/mapred-map-tasks-and-mapred-reduce-tasks-parameter-meaning-tp3766224p3766224.html > Sent from the Hadoop lucene-users mailing list archive at Nabble.com. >
