The Log File Autogrow alert indicates that a log file autogrow occurred on the specified database. For this alert to display, enable monitoring of non-query activities with capturing of autogrow events. Note that you can avoid unnecessarily long reads and poor response time from SQL Server by minimizing the number of Autogrow events occurring in your environment.
This alert is raised based on the diagnostic data collection interval specified in Server Properties. For more information, see Set general server options.
To learn more about how autogrow works and related best-practices, see Microsoft Support Article 315512 , "Considerations for the 'autogrow' and 'autoshrink' settings in SQL Server".