There is a hard coded default of 50% of jvm heap when global-max-size is not specified. To allow the percentage to be configured and to avoid an absolute number in the config, it would be ideal to be able to configure the percentage.

In container land, where the jvm is container aware and has a configureable % of memory, allowing the broker to use a configurable % is intuitive.

it can default to 50% to retain existing behaviour.

there is a hardcoded 50% when the global max size in not configured. https://github.com/apache/activemq-artemis/blob/1d1f03ad5e2644b558b5eb65f737665b24[…]e/activemq/artemis/api/config/ActiveMQDefaultConfiguration.java