How To Fix CSM_VMC063 - Average Frequency of Full GCs for All Virtual Machines

SAP Error Message - Details

• Message type: E = Error

• Message class: CSM_VMC - Messages for VM Container Monitoring

• Message number: 063

• Message text: Average Frequency of Full GCs for All Virtual Machines

What causes this issue?

Each of the active virtual machines in the VM Container has reserved
memory for its Java heap. The size of this memory is bound to specified
limits when the VM is started and cannot be changed at runtime. Once
this memory is used up, the VM activates the garbage collection (GC)
procedure, in which memory allocated but no longer needed is freed up
again. There are two stages to this procedure - partial and full
garbage collection. The partial GC only cleans up dedicated memory areas
and therefore is much quicker than the full GC, and uses less resources.
This partial GC is performed more frequently and is part of normal
operation. The full GC is started when the permanent memory usage
(objects that have survived several partial GCs) exceeds specified
limits. The full GC clears all objects that are no longer needed in the
Java heap, reducing the memory usage to the lowest possible level. This
process involves a complex analysis of the Java object references and
takes a long time and uses up alot of VM resources.

System Response

This monitor displays the average frequency of full GC runs in all
virtual machines in the VM Container. A frequency of several full GCs
per minute (10 and over) indicates that the VM memory is becoming low in
each of the active VMs, and this can affect system performance
considerably.
You can find more information in the online documentation under
<DS:KENO.001560AA0E081DEB91FE7CAB73A45918>Garbage Collection</>.

How to fix this error?

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message CSM_VMC063 - Average Frequency of Full GCs for All Virtual Machines ?

  The SAP error message CSM_VMC063, which refers to the "Average Frequency of Full GCs for All Virtual Machines," typically indicates that the Java Virtual Machine (JVM) is experiencing frequent full garbage collections (GCs). This can lead to performance issues in your SAP application, as full GCs can be time-consuming and can cause application pauses.
  Cause:
  
  Memory Pressure: The JVM may not have enough heap memory allocated, leading to frequent full GCs as it tries to reclaim memory.
  Memory Leaks: There may be memory leaks in the application, causing objects to remain in memory longer than necessary.
  Improper GC Configuration: The garbage collection settings may not be optimized for the workload, leading to inefficient memory management.
  High Object Creation Rate: If the application creates a large number of objects quickly, it can lead to increased GC activity.
  Large Object Allocation: Allocating large objects can trigger full GCs more frequently.
  
  Solution:
  
  Increase Heap Size: Review and increase the maximum heap size allocated to the JVM. This can be done by adjusting the -Xmx parameter in the JVM options.
  Analyze Memory Usage: Use tools like VisualVM, JConsole, or SAP's own monitoring tools to analyze memory usage and identify potential memory leaks or high object creation rates.
  Optimize Application Code: Review the application code for inefficiencies, such as unnecessary object creation or holding references to objects longer than needed.
  Tune Garbage Collection Settings: Experiment with different garbage collection algorithms and settings. For example, consider using the G1 garbage collector or adjusting the parameters for the existing GC.
  Monitor and Adjust: Continuously monitor the application performance and GC activity. Adjust the heap size and GC settings based on observed behavior.
  Upgrade Java Version: If you are using an older version of Java, consider upgrading to a newer version that may have improved garbage collection algorithms and performance.
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to JVM performance and garbage collection for specific recommendations and best practices.
  Documentation: Refer to the official SAP documentation for guidelines on configuring the JVM for SAP applications.
  Performance Monitoring: Utilize SAP Solution Manager or other monitoring tools to keep track of JVM performance metrics, including GC frequency and duration.
  
  By addressing the underlying causes and implementing the suggested solutions, you can reduce the frequency of full GCs and improve the overall performance of your SAP application.