Once upon a time I had an opportunity to decide on a naming scheme. So I went round and asked my developers, who after all were the people who had to work with these names on a day-to-day basis, whether they preferred functional names (that is, names which represent, in some encoded form, the purpose of the machine) or mnemonic names (that is, names drawn from some pre-existing human naming scheme, which contained no implicit content about the machine’s purpose).
Out of 38 developers, 37 preferred mnemonic names; only one preferred functional names. So I named them all after rivers (there’s a very large pool of possible names, and many of them are short, easy to remember, and quick to type).
The human brain is pretty well-designed for attaching meaning to names. If you provide names that are memorable, people will pretty quickly remember what those names are used for, and use them. If you use names drawn from some common background (eg rivers, elements, stars, counties, drinks, you get the idea) it helps people to immediately recognise a company hostname when they come across it; otherwise statements like “all the email ended up on betelgeuse” can be a bit confusing).
Conversely, my developers felt that they had in previous jobs had a really hard time remembering exactly what pr1ms001 was.
But I should add that we used CNAMEs in the internal DNS to provide a functional name to mnemonic name mapping, so if you really found it easier to remember that the main mail server at the first cluster at the PR site was pr1ms001, then the DNS would let you know that that was currently orwell. Also, that let us have many functional names per machine, so as long as you always used the functional name relevant to the function you were working on, you could be sure that pr1imap001 would always point to the IMAP server, even if we moved that functionality from orwell to rhine. And when hudson died, we could change the name of the replacement without affecting operational functions, so that we never had the “do you mean new hudson or old hudson?” confusion.