# AOSPERF02-BP02 Implement Java memory utilization monitoring
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 Keep `JVMMemoryPressure` below 85% to maintain efficient memory utilization and prevent potential performance issues. 

 **Level of risk exposed if this best practice is not established:** High 

 **Desired outcome:** The JVMMemoryPressure metric remains below 85% for efficient memory utilization and minimizing potential performance issues or domain blocks. 

 **Benefits of establishing this best practice:** Closely monitoring `JVMMemoryPressure` helps you identify and address any potential issues related to high memory pressure, such as excessive garbage collection or memory leaks, before they impact your domain's performance, availability and scalability. 

## Implementation guidance
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 To maintain optimal performance and memory utilization for your OpenSearch Service domains, closely monitor the `JVMMemoryPressure` metric. Specifically, track this metric to verify that it remains below the recommended threshold of 85 percent. This helps you identify and address any potential issues related to high memory pressure, such as excessive garbage collection or out of memory problems, before they impact your domain's performance or scalability. 

### Implementation steps
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+  Log in to the AWS Management Console. 
+  Navigate to the Amazon OpenSearch Service console. 
+  Select your OpenSearch Service domain name. 
+  Choose the **Cluster health tab**. 
+  Navigate to the Data nodes box. 
+  Choose the `JVMMemoryPressure` graph. 
+  Adjust time range to `2w` and Statistic to `Maximum`. 

 If you notice that your `JVMMemoryPressure` exceeds 85% over a 14-day period, investigate further by reviewing the best practices outlined in [AOSPERF01](https://docs.aws.amazon.com/wellarchitected/latest/amazon-opensearch-service-lens/architecture-selection.html) as well as reviewing some of the common issues outlined in [How do I troubleshoot high JVM memory pressure on my OpenSearch Service cluster](https://repost.aws/knowledge-center/opensearch-high-jvm-memory-pressure). 

## Resources
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+  [How do I troubleshoot high JVM memory pressure on my OpenSearch Service cluster](https://repost.aws/knowledge-center/opensearch-high-jvm-memory-pressure) 
+  [Troubleshooting Amazon OpenSearch Service](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/handling-errors.html#troubleshooting-cluster-block) 
+  [Choosing the number of shards](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/bp-sharding.html) 
+  [Sizing OpenSearch Service domains](https://docs.aws.amazon.com/opensearch-service/latest/developerguide/sizing-domains.html)