Logs in two different files log4Net - asp.net-mvc-3

Question

I wanted to write logs in two different files using log4net, one in the global log file while the other for particular user file, for this I set the param in appender like this
<param name="File" value="D:\Projects\Web\Web\Services\Log\%property{LogFileName}" />
And defined a function like this
public void AddInfo(string message)
{
log4net.GlobalContext.Properties["LogFileName"] = this.UserId + ".txt";
log4net.Config.XmlConfigurator.Configure();
Logger.Info(message);
log4net.GlobalContext.Properties["LogFileName"] = "ServiceLog.txt";
log4net.Config.XmlConfigurator.Configure();
Logger.Info(message);
}
This all is working find, every log is written in two different files successfully.
My concern is, is the approach correct if we think about performance?
For each and every log it will configure log4net two times, will it affect performance negatively?

Answer 1

Create two file appenders - one for user log (with pattern for file name), and another for global log:
<appender name="UserFileAppender" type="log4net.Appender.RollingFileAppender">
<file type="log4net.Util.PatternString" value="%property{userId}.txt" />
...
</appender>
<appender name="GlobalFileAppender" type="log4net.Appender.RollingFileAppender">
<file value="log.txt" />
...
</appender>
<root>
<level value="DEBUG" />
<appender-ref ref="UserFileAppender" />
<appender-ref ref="GlobalFileAppender" />
</root>
Then configure log4net only once per user:
GlobalContext.Properties["userId"] = "Bob";
XmlConfigurator.Configure();
And use loggers in your application.