DotNetNuke supports the concept of logging
Providers , allowing site owners to decide how core logging occurs. Out of the box DotNetNuke ships with 2 providers the XMLLoggingProvider which was deprecated due to known performance problems (official deprecation date of June 23, 2009). The recommended replacement is the DBLoggingProvider (which has been the default since 3.3)
The default provider definition looks like this from DNN 7.0.0 on:
<logging defaultProvider="DBLoggingProvider">
<providers>
<clear />
<add name="DBLoggingProvider" type="DotNetNuke.Services.Log.EventLog.DBLoggingProvider, DotNetNuke" providerPath="~\Providers\LoggingProviders\DBLoggingProvider\" />
</providers>
</logging>