I’ve been reading a bit over the last couple days about virtualization solutions for servers, specifically VMWare’s Server product. These sort of solutions allow you to run multiple “virtual” machines on one actual physical server, which in some cases means you can take better advantage of under-utilized machines while at the same time creating completely seperate environments (even running different operating systems) that will not conflict with each other.
What strikes me in reading over the VMWare blogs is that the people who seem to be having the most success with the server, in terms of consolidating from 10 machines to 1, or whatever, are those who have large Windows Server installations. They have taken to heart the idea of “one application per server,” which is pretty much what it sounds like — each major application, be it your accounting system, your virus scanner, your mail server, whatever, sits on its own server, completely seperate from everything else. This helps keep things secure and stable, but the trade-off is that you have to get a *lot* of servers, many of which are generally underutilized. Replacing them all with one powerful box and VMWare makes a lot of sense in that case.
In our case, however, we have several machines that *are* well-utilized, and so the propsect of virtualizing, say, a heavily loaded web server or an important database server does not really appeal to me. Thus the inflated performance numbers you might find in the Windows world are somewhat dulled in the Linux world where, I think, its a bit more common to have a few or several different services running per machine, in a fairly secure and stable fashion (or, in the case of our web server, running things in “jails” so that they can’t talk to each other, a much more lightweight form of virtualization that is fairly effective in certain instances).
Still, I’m intrigued, and I’d like to investigate this further, but I don’t really have any machines to spare right now on this sort of thing. It doesn’t help that I can’t find much in the way of peoples experiences with VMWare Server in Linux or UNIX environments, not to mention the complete lack of published benchmarks. I’ll keep looking, and if anyone has any suggestions, do pass them along.