Hyper V Manager showing 32GB RAM available, but I have 48GB Ram installed in server

Available memory is too low in the management operating system

Hyper-V automatically calculates an amount of memory to reserve for exclusive use by the management operating system. This memory is used to run virtualization services. If the computer is part of a failover cluster, Hyper-V also reserves enough memory to run the failover cluster services. However, if the management operating system rums other roles or features, the amount of reserved memory might be too low. You can specify a larger amount of memory by modifying the registry. ......


http://technet.microsoft.com/en-us/library/ff817651(v=WS.10).aspx

also you could check this tread too:

https://www.experts-exchange.com/questions/27080005/Hyper-V-Not-enough-memory-in-the-system-to-start-the-virtual-machine.html

ThePhysical server is 64bit and it is just a configured box running the HyperV services, that's it.  The other OS's and DC's are in Virtuals (Yes I know the warnings of DC's in HyperV)

HyperV did not reserve enough Memory?

I read your links, I do not see NUMA spanning listed in the options for the HYPER-V settings, on another Host I did see this setting available....why on one and not another, is there a place where I need to install NUMA spanning?

Please confirm, your HOST operating system is - you are CERTAIN - Enterprise?  Or is it standard?  Enterprise should definitely see more RAM.  Standard will not.

And if you're not running any explicitly memory hungry applications, I recommend making use of Dynamic RAM settings.

Which edition of server?

It could be this, which I've seen before

enable Numa Spanning in Hyper-V settings.

Here is some information on NUMA memory handling and what it is:

http://en.wikipedia.org/wiki/Non-Uniform_Memory_Access

And here is a good article about Dynamic memory handling in Hyper-V:

http://www.virtualizationadmin.com/articles-tutorials/microsoft-hyper-v-articles/installation-and-deployment/using-dynamic-memory-Hyper-v-r2-sp1.html

The server is server 2008 standard (host physical) with 48GB RAM showing 64bit

I do not see the NUMA feature available in the Hyper-V properties (I have seen this on other servers though)

Crap Svet...you are right, ImaCir already had it out of the gate....ugh, I guess I'll have to do a planned outage to upgrade the host...bummer, didn't see that one coming.  Thanks guys for the help!

So you were using Standard and not Enterprise as per Question?

That is correct, I was using Standard instead of enterprise

It's worth checking the fundamentals first.  Usually saves you a lot of time!  Glad I could help.