Log4Net Logging of two different levels to two different appenders for the same logger

Question

We have two different asp.net applications with Log4net logging enabled. They both have the same version of Log4Net, 1.2.10.0.

We have added the log4net.Append

Answer 1

You could specify a LevelRangeFilter for each of the appenders, and define each appender in the root to log at different levels.

<appender name="filelogAppender" type="log4net.Appender.RollingFileAppender" >
    <!--File Details/Layout Options-->
    <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="INFO"/>
    </filter>
</appender>
<appender name="dbLogAppender" type="log4net.Appender.AdoNetAppender">
    <!--SQL Options-->      
    <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="ERROR"/>
    </filter>
</appender>
<root>
    <level value="INFO"/>
    <appender-ref ref="filelogAppender" /> <!--Prints info, warn, error, or fatal logs. -->
    <appender-ref ref="dbLogAppender" />   <!--Prints only error or fatal logs. -->
</root>

Answer 2

Simply use Evaluator, you do not need to give threshold in all the appenders.

<appender name="filelogAppender" type="log4net.Appender.RollingFileAppender">
        <evaluator type="log4net.Core.LevelEvaluator">
          <threshold value="ERROR" />
  </evaluator>
</appender>

Answer 3

You should be able to set the threshold property of each appender separately and include them in the same root.

<appender name="filelogAppender" type="log4net.Appender.RollingFileAppender">
  <threshold value="Error" />
</appender>
<appender name="dblogAppender" type="log4net.Appender.AdoNetAppender">
  <threshold value="Info" />
</appender>
<root>
  <appender-ref ref="filelogAppender" />
  <appender-ref ref="dblogAppender" />
</root>

reference

Answer 4

Two <root> elements are not allowed.

From documentation:

root     Optional element, maximum of one allowed. Defines the configuration of the root logger.

You can however have a root logger like you do, and then have a separate logger specified by a namespace.

<root>
    <level value="Error"/>
    <appender-ref ref="filelogAppender"/>
</root>
<logger name="MyCompany.MyApp.Namespace">
    <level value="Info"/>
    <appender-ref ref="dbLogAppender"/>
</logger>