https://community.cloudera.com/t5/Support-Questions/MapReduce-application-failed-with-OutOfMemoryError/m-p/56021#M36633 I don't know of anything that would allow it to read the configuration files from the other file. The difference in mapred and mapreduce settings is the MR API. I think it is possible then that the MR app you have is using the older API and maybe that is why the mapred settings were working before.<BR /><BR />You can check the configuration settings for each MR job through the RM UI. Use that to verify the exact settings used in each settings.<BR /><BR />On the resource usage, the number of maps is determined by the input. Are you positive that the same amount of data and blocks was being used by the app in each run? Fri, 16 Jun 2017 17:12:26 GMT mbigelow 2017-06-16T17:12:26Z