elasticsearch/docs/reference/setup/important-settings/heap-size.asciidoc

[[heap-size-settings]]
[discrete]
=== Heap size settings

By default, {es} automatically sizes JVM heap based on a node's
<<node-roles,roles>> and total memory. We recommend this default sizing for most
production environments. If needed, you can override default sizing by manually
<<setting-jvm-heap-size,setting JVM heap size>>.

NOTE: Automatic heap sizing requires the <<jvm-version,bundled JDK>> or, if using
a custom JRE location, a Java 14 or later JRE.

NOTE: When running in a container, such as <<docker,Docker>>, total memory is
defined as the amount of memory visible to the container, not the total system
memory on the host.