Troubleshooting

This page provides a list of common questions you might encounter while using Axon Server to help you trouble shoot your instances. If your scenario is missing, be sure to reach out to us directly for more help!

My messages are too large, what should I do?

Some application connecting to Axon Server might send messages that exceed the maximum message size. When this is the case, Axon Server will throw a clear exception stating the maximum message size has been exceeded.

Although the max-message-size of Axon Server can be adjusted, it is wise to check whether the sending application is behaving as desired. The default of 4 MB per message is typically sufficient, so exceeding this limit should raise warnings.

Scenarios when applications would exceed the max-message-size are:

  • The message contains an image.

  • The message contains a (large) document.

  • The event transaction contains a lot of events in total. When publishing multiple events, Axon Server intends to group those in a single message for consistency.

If after validation the message proofs to be as desired, it is fair to adjust the max-message-size. Be sure to change this property on all Axon Server nodes, as well as the connected applications when doing so!

What are the replication logs?

The Replication Logs (by default stored in the logs folder) are part of Axon Server’s distributed consensus implementation to ensure all instances arrive at the same conclusion. As such, they are part of our RAFT implementation and of utmost importance to maintain a consistent state.

If you want to learn more about them, please check out the Replication Logs section for more information.

When can I remove the Replication Logs?

We do not recommend you to remove the replication logs without consulting with AxonIQ. They are so important for the correct working of Axon Server that the chances are extremely slim that removal of the logs is the way forward.

For a more detailed explanation of the Replication Logs and how to deal with them, we recommend you read the following section.

What is the Control Database / controlDb?

The Control Database for Axon Server maintains a ton of important configuration data of Axon Server. For example, the user configuration is maintained in the controlDb, on each instance you would be running.

If you want to learn more about it, please read the dedicated Control Database section for more information.

When can I remove the controlDb?

We do not recommend you to remove the controlDb without consulting with AxonIQ. It is so important for the correct working of Axon Server that the chances are extremely slim that removal of the controlDb is the way forward.

For a more detailed explanation of the Control Database and how to deal with it, we recommend you read the following section.