The Average Memory Usage of an Elasticsearch Cluster Reaches 98%

Symptom

The cluster monitoring result shows that the average memory usage of a cluster is 98%. Does it affect cluster performance?

Possible Cause

In an ES cluster, 50% of the memory is occupied by Elasticsearch and the other 50% is used by Lucene to cache files. It is normal that the average memory usage reaches 98%.

Solution

You can monitor the cluster memory usage by checking the maximum JVM heap usage and average JVM heap usage.