I’ve been trying to find specific guidance for some time on the size of a pagefile as recommended by Microsoft for a system running as a Hyper-V host. The theory is that on a Hyper-V host, Windows itself should never really use a page file at all. As a result, I’ve been setting page file to be 4GB – enough in case it’s needed, but not huge as we don’t need to waste disk space on something that in my mind is never going to be used. Now I should be clear here – I’m talking about the HOST on which Hyper-V runs, not the GUEST machines that run ON Hyper-V Hosts. Guest machines should be configured as per their respective applications require.
With Window Server 2012 however, Microsoft changed that, and I recently found that they recommended the following.
For Windows Server 2012 Hyper-V and Windows Server 2012 R2 Hyper-V, the page file of the management OS (commonly called the host OS) should be left at the default of setting of "System Managed." This is per the Hyper-V product group.
This comes from a Microsoft KB article on how to configure a Page file for a 64 bit system here
It’s important to note that this information is relevant ONLY to Windows Server 2012 and 2012 R2 with Hyper-V roles installed. Previous versions of Hyper-V do not benefit from the same improvements and as such do still need to be tuned/tweaked.