Since I have 2 virtual servers providing log files, how can I activate the option for multiple virutal servers?
You want to blank out the servername option completely, and set the manyservers option. To be clear: leave servername blank, or remove the line for it entirely. Along those lines if you have several websites which have multiple domain names such as www.site.foobar.com, www.site.foo.com etc. There is a method that to make Wusage produce a report for all the domain names belonging to the particular site. It is the “manyservers” option in our configuration file editor (“Analyze ALL Virtual Servers Found In Log File”).