This article describes the reason of high memory utilization on the node process.
In FortiOS 6.4, node process functionality is limited to generating security rating report and maintaining CLI console widget when accessing the Fortigate via HTTP/HTTPS.
In FortiOS 7.0 onwards, node process is responsible to process all incoming HTTP/HTTPS request including REST API (node process is a new GUI server daemon responsible for GUI administration).
The security rating result submission is by default enabled on the FortiGate, this feature enables submission of security rating results to Fortiguard for data collection purposes/continuous learning and memory intensive, it could lead to high memory usage observed on the node process.
To disable the functionality, execute the following command:
# config system global set security-rating-result-submission disable end