OutOfMemoryError: Metaspace on OpenShift/Kubernetes This can be a precious hint to determine if a Classloader is loading an increasing number of classes. Other interesting options include the parameter -gcutil: $ jstat -gcutil (PID) | awk ''), 'lhs.count < rhs.count'), 'toHtml(it) + " YGC: Number of young generation GC events.CCSMX: Compressed class space maximum capacity (kB).CCSMN: Compressed class space minimum capacity (kB).When used with the option -gcmetacapacity it provides the following information: jstat -gcmetacapacity (PID)įor example: MCMN MCMX MC CCSMN CCSMX CCSC YGC FGC FGCT CGC CGCTĠ.0 374784.0 140360.0 0.0 253952.0 21168.0 23 0 0.000 6 0.046 The simplest way to monitor the MetaSpace size is by means of the jstat tool which is available in the JDK. When the space committed for class Metadata reaches a certain threshold (a high-water mark), a Garbage Collection happens.Īfter the Garbage Collection, the high-water mark may change depending on the amount of space freed from class Metadata. Java classes are unloaded as a result of Garbage collection, and garbage collections may be triggered in order to unload classes and deallocate class Metadata. A class loader allocates space for Metadata from its chunks.Ĭlass Metadata is deallocated when the corresponding Java class is unloaded and its chunks are recycled for reuse or returned to the OS.
The Java Hotspot manages Metadata space as follows: firstly, the JVM requests an amount of space to the OS. Check the Heap dump of your application to find offending Classes.
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Learn how to monitor the MetaSpace in a running Java application.Understand how the JVM manages the MetaSpace data.In order to find the Root cause, we recommend that you follow these steps: On the other hand, if you see this error at runtime, we recommend to investigate on the Root cause of the problem before increasing blindly the MaxMetaspaceSize. This is quote true if you can see the error upon application start up. What is the solution ?īy increasing the upper limit of the attribute MaxMetaspaceSize you are likely to solve the issue. That can however not be greater than 230% of the occupancy after the GC cycle.
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In fact, there is a setting called MaxMetaspaceFreeRatio (default 70%) which means that the actual metaspace size will never exceed 230% of its occupancy.Īnd for it to grow it first would have to fill up, forcing a garbage collection in an attempt to free objects and only when it cannot meet its MinMetaspaceFreeRatio (default 40%) goal it would expand the current metaspace.
The thing is that -XX:MaxMetaspaceSize is just an upper limit. On the other hand, if you want to limit the amount of memory allocated for Java classes, you can set it as follows: java -XX:MaxMetaspaceSize=3200m In Java 8 and later, the maximum amount of memory allocated for Java classes ( MaxMetaspaceSize) is by default unlimited, so in most cases there is no need to change this setting.
Let’s how this issue can be solved in standalone applications and cloud applications. The : Metaspace indicates that the amount of native memory allocated for Java class metadata is exausted.
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