Thanks for your answers!
From: Marcos Ortiz <[email protected]<mailto:[email protected]>> Date: Thu, 1 Nov 2012 19:03:23 +0100 To: peter cogan <[email protected]<mailto:[email protected]>> Cc: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: Re: Set the number of maps The option since 0.21 was renamed to mapreduce.tasktracker.map.tasks.maximum, and like Harsh said to you, is is a TaskTracker service level option. Another thing is that this option is very united to the mapreduce.child.java.opts, so , make sure to monitor constantly the effect of these changes in your cluster. On 11/01/2012 11:55 AM, Harsh J wrote: It can't be set from the code this way - the slot property is applied at the TaskTracker service level (as the name goes). Since you're just testing at the moment, try to set these values, restart TTs, and run your jobs again. You do not need to restart JT at any point for tweaking these values. On Thu, Nov 1, 2012 at 7:13 PM, Cogan, Peter (Peter) <[email protected]><mailto:[email protected]> wrote: Hi I understand that the maximum number of concurrent map tasks is set by mapred.tasktracker.map.tasks.maximum - however I wish to run with a smaller number of maps (am testing disk IO). I thought that I could set that withinthe main program using conf.set("mapred.tasktracker.map.tasks.maximuma", "4"); to run with 4 maps – but that seems to have no impact. I know I could just change the mapred-site.xml and restart map reduce but that's kind of a pain. Can it be set from within the code? Thanks Peter -- Marcos Luis Ortíz Valmaseda about.me/marcosortiz<http://about.me/marcosortiz> @marcosluis2186<http://twitter.com/marcosluis2186> [http://universidad.uci.cu/email.gif]<http://www.uci.cu/> <http://www.uci.cu/> <http://www.uci.cu/> <http://www.uci.cu/> <http://www.uci.cu/>
