[ https://issues.apache.org/jira/browse/MAPREDUCE-68?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Harsh J resolved MAPREDUCE-68. ------------------------------ Resolution: Not A Problem Not a problem with current release schedulers. > Hadoop reduce scheduler sometimes leaves machines idle > ------------------------------------------------------ > > Key: MAPREDUCE-68 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-68 > Project: Hadoop Map/Reduce > Issue Type: Bug > Reporter: Nathan Marz > > I have a MapReduce application with number of reducers equal to the number of > machines in the cluster (and with speculative execution turned off). However, > Hadoop schedules multiple reduces to run on single machines and leaves other > machines idle. This causes contention and seriously slows down the job. > Hadoop should employ the simple heuristic of utilizing as many machines as > possible when scheduling reduces. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira