What must you do if you change the log level in the Zabbix configuration file?

When the log level is changed in the Zabbix configuration file, it is essential to restart the Zabbix server for the changes to take effect. This is because the server reads its configuration settings, including the log level, from the configuration file upon startup. By restarting the server, Zabbix can apply the new log level setting, which will affect how logging information is processed and stored.

Not taking any action or attempting to reload other services like the web server would not apply the new log level since they are not responsible for reading the configuration of the core Zabbix server. Changing settings without a proper restart could leave the system using the old logging parameters, which would not give the desired output or behavior intended by modifying the log level.