The other day, one of our developers (who’s preparing to be a DBA, by the way– whoo!) asked me how to set up an alert if the transaction log grows alarmingly. Now I searched SQL Server Agent>Alerts inside SQL Server management studio, but couldnt find this. Recently, I found that this is possible through the Windows tool named "Performance" which you can open by typing "perfmon" in Start>Run.
There is a section called "Performance Logs and Alerts" which you need to expand. This lets you define a new alert.
There are various counters here that you can use. The one of interest to us is "MSSQL$2005:Databases. This counter has various counters which you can read online, so I am not repeating that here. I selected the "Log Growths" parameter for a specific database (named gLock).
You can set this to an appropriate value and set it to do various actions that you define.
Hope this was useful…