To illustrate the possibilities, we will run two copies of Apache with different IP addresses on different consoles, as if they were on two completely separate machines. This is not something you want to do often, but for the sake of completeness, here it is. Normally, you would only bother if the different virtual hosts needed very different configurations, such as different values for ServerType, User, TypesConfig, or ServerRoot (none of these directives can apply to a virtual host, since they are global to all servers, which is why you have to run two copies to get the desired effect). If you are expecting a lot of hits, you should try to avoid running more than one copy, as doing so will generally load the machine more.
In our case, we don't have any real need to run two copies; however, we will go this route for the sake of education. You can find the necessary machinery in ... /site.twocopy. There are two subdirectories: customers and sales.
The Config file in ... /customers contains the following:
User webuser Group webgroup ServerName www.butterthlies.com DocumentRoot /usr/www/site.twocopy/customers/htdocs BindAddress www.butterthlies.com TransferLog logs/access_log
In ... /sales the Config file is:
User webuser Group webgroup ServerName sales.butterthlies.com DocumentRoot /usr/www/site.twocopy/sales/htdocs Listen sales-not-vh.butterthlies.com:80 TransferLog logs/access_log
On this occasion, we will exercise the sales-not-vh.butterthlies.com ...