Hi!
I hope you are well today and thank you for using the Wazuh Community!
About your question,
The JSON log format is almost always preferred over other formats, as Wazuh has a default JSON decoder, so there is no need to write custom decoders for these logs, as is sometimes the case with other log formats.
In the case of Suricata logs, the JSON logs include much more information and this can be very useful when analyzing the alerts in the Wazuh-dashboard, or when writing custom rules.
Please note that by default, Wazuh only writes alerts for events that are matched by rules of level 3 or higher (default value), not necessarily every log sent to Wazuh will be written to the alerts.json file or be indexed in the Wazuh-indexer.
There is a tool in Wazuh that you can use to check if the logs you want to ingest will be decoded or not with the default decoders or if you will need to write a custom one. This tool also lets you know if a rule would be matched or if you will need to write a custom rule to generate alerts for these events. This could probably help you determine if the default Suricata log format would provide enough information for your needs or if you would still prefer to use the recommended JSON format.
Here you can find more information about ingesting Suricata logs in Wazuh:
I hope this information is helpful,
Ariel.