Configure memory settings
The memory configuration for YARN and MapReduce memory is important to get the best performance from your cluster.
Several different settings are involved. The table below shows the default settings, as well as the settings that Cloudera recommends, for each configuration option.
| Cloudera Manager Property Name | Cloudera Runtime Property Name | Default Configuration | Cloudera Tuning Guidelines |
|---|---|---|---|
| Container Memory Minimum | yarn.scheduler.minimum-allocation-mb |
1 GB | 0 |
| Container Memory Maximum | yarn.scheduler.maximum-allocation-mb |
64 GB | amount of memory on largest host |
| Container Memory Increment | yarn.scheduler.increment-allocation-mb |
512 MB | Use a fairly large value, such as 128 MB |
| Container Memory | yarn.nodemanager.resource.memory-mb |
8 GB | 8 GB |
| Map Task Memory | mapreduce.map.memory.mb |
1 GB | 1 GB |
| Reduce Task Memory | mapreduce.reduce.memory.mb |
1 GB | 1 GB |
| Map Task Java Opts Base | mapreduce.map.java.opts |
-Djava.net.preferIPv4Stack=true | -Djava.net.preferIPv4Stack=true -Xmx768m |
| Reduce Task Java Opts Base | mapreduce.reduce.java.opts |
-Djava.net.preferIPv4Stack=true | -Djava.net.preferIPv4Stack=true -Xmx768m |
| ApplicationMaster Memory | yarn.app.mapreduce.am.resource.mb |
1 GB | 1 GB |
| ApplicationMaster Java Opts Base | yarn.app.mapreduce.am.command-opt |
-Djava.net.preferIPv4Stack=true | -Djava.net.preferIPv4Stack=true -Xmx768m |
