Reference:
Using FortiAnalyzer, you can enable log fetching. This allows FortiAnalyzer to fetch the archived logs of specified devices from another FortiAnalyzer, which you can then run queries or reports on for forensic analysis.
The FortiAnalyzer device that fetches logs operates as the fetch client, and the other FortiAnalyzer device that sends logs operates as the fetch server. Log fetching can happen only between two FortiAnalyzer devices, and both of them must be running the same firmware version. A FortiAnalyzer device can perform either the fetch server or client role, and it can perform two roles at the same time with different FortiAnalyzer devices at the other end.
FortiAnalyzer_7.0_Study_Guide-Online pag. 168

Events in FortiAnalyzer will be in one of four statuses. The current status will determine if more actions need to be taken by the security team or not.
The possible statuses are:
Unhandled: The security event risk is not mitigated or contained, so it is considered open.
Contained: The risk source is isolated.
Mitigated: The security risk is mitigated by being blocked or dropped.
(Blank): Other scenarios.
FortiAnalyzer_7.0_Study_Guide-Online pag. 206