How can I measure whether my site is fast enough?
Many developers test their sites locally or over an internal network, but if you run a public Web site, chances are good that many of your users will access it over slow links. Try navigating your Web site from a dialup account and make sure that your pages load fast enough, with the rule of thumb being that pages should load in less than three seconds.
How can I migrate an existing name-based virtual host to its own machine while maintaining continuous service?
If a virtual host is destined to move to a neighboring machine, which by definition cannot have the same IP address, there are some extra measures to take. A common practice is to do something like the following, although many variations on these steps are possible:
Set the time-to-live (TTL) of the DNS mapping to a very low number. This increases the frequency of client lookups of the hostname.
Configure an IP alias on the old host with the new IP address.
Configure the virtual host's content to be served by both name- and IP-addressbased virtual hosts.
After all the requests for the virtual host at the old IP address diminish (due to DNS caches expiring their old lookups), the server can be migrated.
Can I mix IP- and name-based virtual hosting?
Yes. If multiple IP addresses are bound, you can allocate their usage a number of different ways. A family of name-based virtual hosts might be associated with each; just use a separate NameVirtualHost directive for each IP. One IP might be dedicated as an IP-based virtual host for SSL, for instance, whereas another might be dedicated to a family of name-based virtual hosts.