Known Limitations
This page describes concerns and limitations that should be considered when allocating resources to a9s Messaging plans, as well as other known issues.
Caveats regarding Backups
When creating a backup for a9s Messaging, please note that only the queue definitions are stored. The actual messages within the queues are not saved, as this service is designed for non-persistent queues.
When restoring a backup, any missing queues will be added to the service. Meanwhile, the existing queues and their corresponding data, that existed before the backup was created, will be preserved.
Object Size Limit
a9s Messaging's underlying RabbitMQ service has a hard limit of 16 MiB for object sizes, however, publishing messages anywhere near that size is discouraged if there is uncertainty over the Virtual Machine's available resources being large enough to handle it. The reason behind this is that if the VM is not big enough, such messages may cause the underlying service to misbehave when the usage reaches a level comparable to the available resources. This happens because any message of a size close to it pins massive RAM in every queue, multiplies disk I/O, and can block connections long enough to trigger false fail-overs. Therefore, sluggish, or even briefly unavailable, Service Instances will be noticeable well below the limit. For more information, please check RabbitMQ limits documentation.