Someone on another website said this:
I have to question why you would run 3 different servers to do this and then want them to be on standby. Why wouldnt you just run your DC and exchange on the same server? Not a MS best practice but it can be done without a hitch. And why a secondary DC? If you want them to be on stand by then its apparent that high availability is of not much concern.
There is also the virtualization option. You could run your dc on a server and then put exchange on a virtual server. In this case a secondary DC would again be pointless. Unless you are just fiddling which you could run the secondary on a virtual server as well.
He basically is telling me to put Exchange on a Domain Controller or Put it in MS Virtual Server on my DC.
I am not familiar with ESX Server, but I tested it already and I find its really good with the exception of locking myself out of the console and have a terrible file server support, but I think I might decide to use that, if I can connect my internet direcly to my DC while making my DC the main file server.
About my mainstream server, here is what you seem to miss out of:
I would upgrade the RAM on the other server to even 8GB if possible and install VMWare ESXi on it
My server only goes up to 3.24 GB of RAM and I put 4 GB on it. The motherboard on the Server is an 8i945gmh-rh Gigabyte Motherboard and I wish it would support all 4 GB of RAM in a 64 bit operating system. Maybe I should replace it with my ASUS P5B-E or something?
I am thinking of just using 3 servers and not bother about virtualization, because:
One server has 2 NICs and it can be a perfect Terminal Server and an Internet Gateway
One server has has enough room for ESXi or a File Server and Domain Controller, or I can use Exchange Server 2007 by using 64 bit Windows on it.
One server is just a 32 bit box which can perfectly be a file server and I used it to run Exchange Server 2003 for about 3 years already. I was thinking of making this into a desktop workstation instead of using it as a server. It was my old desktop.
Another thing, I do not have a licence for Windows Server 2008 and I have licences for Windows Server 2003. Unless someone can give me one or I can use my own 2003 licences or maybe even get an illegal one or something which will work perpectually, I am stuck with 2003.