XG330 : Very high cpu usage for Garner service??

Garner is basically the reporting daemon. So it looks like, you have a high volume of reports or a broken database.

Can you check, if your reports (Logviewer / Reporting) on box works? 

If there are no reports anymore, check the log size: https://support.sophos.com/support/s/article/KB-000035777?language=en_US

Try to restart the daemon. 

we should know what service needs to be restarted for garner process.

Julian Cast in our case there is a lot of RED logging in the garner.log file. Maybe one device is going banana?

And tail -f the syslog.log file if there is excessive logging happening.

we should know what service needs to be restarted for garner process.

Julian Cast in our case there is a lot of RED logging in the garner.log file. Maybe one device is going banana?

And tail -f the syslog.log file if there is excessive logging happening.

SFV6C8_AZ01_SFOS 18.0.4 MR-4# service garner:restart -ds nosync
200 OK