This chapter provided information on Apache and operating system settings that can affect scalability and performance. In most cases, the problems in Web site scalability relate to dynamic content generation and database access. Writing efficient scripts will alleviate issues in those categories. Hardware-related improvements, such as high-quality network cards and drivers, increased memory, and disk arrays can also provide enhanced performance.
With regards to virtual hosting, Apache can be configured to handle virtual hosts in a variety of ways. Whether you need a large number of cookie-cutter virtual hosts, a varied set of different virtual host configurations, or the number of IP addresses you can use is limited, there's a way to configure Apache for your application. Name-based virtual hosting is a common technique for deploying virtual hosts without using up IP addresses. IP-based virtual hosting is another method when you have plenty of IPs available and you want to keep your configuration tidy, with a one-to-one balance of IPs to virtual hosts. Also, if you cannot change your DNS configuration, you have the recourse of using separate port numbers for your virtual hosts.