My good friend, Aidan Finn, has a post on his blog about Host Memory Sizing for Windows Server 2012 Hyper-V.  In his post, he makes this statement:

Microsoft says that the Management OS should have at least 512 MB. That’s being a bit ambitious; I go with 2 GB when I size.

I’m afraid I’m going to have to disagree.  As I posted earlier, I recommend FOUR GB of RAM for the host at an absolute minimum.  My reasoning is very simple:  While I know we all go out of our way to make certain the host is only running Hyper-V, that isn’t always true.  We do sometimes have other things we must do.  And we all know how Windows loves RAM.  Maybe an update is RAM hungry whilst being installed.  Maybe you have automated scripts that run.  Something.  Anything.  Doesn’t matter.  The point is that the last thing we want is the host running low on juice.  And, RAM is cheap so there are no excuses. 

That being said, do let me be clear that my disagreeing with Aidan is not something I do lightly.  Aidan is a great guy, a good friend, and a renowned expert in virtualization.  He is also a published author with two books here and here at Amazon.com.  Please feel free to follow everything else he does without question and without hesitation.

James