We are hosting Artemis broker in Kubernetes using operator-based solution. We deploy the broker as statefulset with 2 or 4 replicas. We assign for e.g. 6 GB for heap and 9 GB for pod, 1.2 GB (1/5 of max heap) for global-max-size. All addresses normally use -1 for max-size-bytes but some less frequently used queues are defined with 100KB for max-size-bytes to allow early paging.
We need some information or documentation link to address following queries. 1. When artemis broker starts up, does it need to first load all persistent messages in memory to be ready for normal broker operations? E.g. if we stop broker with viz. 4 GB of persistent pending messages, does it need min 4 GB of free memory at startup to load these messages? 2. If it uses heap memory for this work or non-heap memory is used for this? 3. If we have defined global-max-size of 1.2 GB and address-full-policy is PAGE and broker has 4 GB of persistent pending messages, will broker first load 1.2 GB of messages in memory from all addresses for faster delivery and rest messages will remains on disk? Or first all messages must be loaded in memory and then paging starts afterwards by keeping 1.2 GB in memory and pushing rest to disk again? 4. If a message is of 10KB, does broker need exact 10KB to store the messages in memory and disk? Or additional space is needed for metadata or encoding etc.? Best Regards, Shiv
