All Integration Services tasks and containers support a default set of events for logging. These events typically represent different stages in the "lifetime" of the object at run time, such as "OnPreExecute", "OnPostExecute", and "OnError".
Many tasks also support custom log entries that may be of more interest to you than the generic events. You can find a list here in BOL (although I see that the list isn't 100% up to date): Custom Messages for Logging. A handful of the interesting custom log entries are... [More]