Monitoring heap memory usage
You can use several ways to monitor the heap memory usage: Cloudera Manager, NameNode web UI, or the command line.
- Cloudera Manager: Look at the NameNode chart for heap
            memory usage. If you need to build the chart from scratch, run:
            
select jvm_max_memory_mb, jvm_heap_used_mb where roleType="NameNode" - NameNode Web UI: Scroll down to the Summary and look for "Heap Memory used."
 - Command line: Generate a heap dump.
 
