Why is the SysMemoryUtilization so high on my OpenSearch Service cluster?

Resolution

You aren't required to scale up the size of your OpenSearch Service cluster when your system memory utilization is over 90%. A high percentage of system memory utilization is normal and doesn't cause heap usage issues or overload your cluster.

The SysMemoryUtilization metric indicates the percentage of the instance's memory that's in use. OpenSearch Service uses most of its memory for in-memory data structures and off-heap buffers. The Java virtual machine (JVM) also requires memory.

To determine whether you must scale up your cluster, use Amazon CloudWatch alarms to monitor the following metrics:

• JVM memory pressure
• CPU utilization
• Free storage space

For more information, see Instance metrics.

Note: It's a best practice to create alarms for each of the recommended CloudWatch alarm metrics for OpenSearch Service.

Related information

How do I scale up or scale out an OpenSearch Service domain?