"What size do you want to be?" it asked.
"Oh, I'm not particular as to size," Alice hastily replied; "only one doesn't like changing so often, you know . . . "
"Are you content now?" said the Caterpillar.
"Well, I should like to be a little larger, sir, if you wouldn't mind . . . "
We set up two nameservers in Chapter 4. Two servers are as few as you'll ever want to run and, depending on the size of your network, you may need to run many more. It is not uncommon to run four or more nameservers, with one of them off-site. How many nameservers are enough? You'll have to decide that based on your network. Here are some guidelines to help out:
Run at least one nameserver on each network or subnet you have. This removes routers as a point of failure. Make the most of any multihomed hosts you may have because they are (by definition) attached to more than one network.
If you have a file server and some diskless nodes, run a nameserver on the file server to serve this group of machines.
Run nameservers near, but not necessarily on, large multiuser computers. The users and their processes probably generate a lot of queries, and, as an administrator, you will work harder to keep a multiuser host up. But balance their needs against the risk of running a nameserver—a security-critical server—on a system to which lots of people have access.
Run at least one nameserver off-site. This makes your data available when your network isn't. You might argue ...