java.lang:type=Memory/NonHeapMemoryUsage reporting crazy values

[Andrew Parrott]

Hi,

Seeing some crazy values returned for non-heap memory with JRE 1.8.0_31 and Tomcat 7-7.0.37:

curl -k http://x.x.x.x:8080/administration/read/java.lang:type=Memory/NonHeapMemoryUsage

{"request":{"mbean":"java.lang:type=Memory","attribute":"NonHeapMemoryUsage","type":"read"},"value":{"init":2555904,"committed":65732608,"max":-1,"used":64150864},"timestamp":1446124009,"status":200}

Stats from the same for heap memory looks fine:

curl -k http://x.x.x.x:8080/administration/read/java.lang:type=Memory/HeapMemoryUsage

{"request":{"mbean":"java.lang:type=Memory","attribute":"HeapMemoryUsage","type":"read"},"value":{"init":2147483648,"committed":2058354688,"max":7635730432,"used":110340376},"timestamp":1446124009,"status":200}

This was from using the latest jolokia-war-1.3.2.war.

Trying to setup event monitoring with Centreon, but looks like we can only monitor for heap memory utilisation for now.

Anyone seen this before please?

[roland]

You mean this -1 in "max" ? Thats because you are running under Java 8 where there is no maximum NonHeapMemory anymore (but can grow into the Heap is exhausted). In fact this was replaced by "Metaspace" (which can be monitored on its own).

For Java 6 and 8 there is still PermGenSpace for this.

See http://stackoverflow.com/questions/18339707/permgen-elimination-in-jdk-8 for a bit more information.