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

Hey there, I have a server 2008 R2 enterprise server with 3VM's running right now.
Physical server has 48GB RAM

VM1=4096MB
VM2=16384MB
vm3=4096MB

I go to create a 4th VM and assign 16384MB RAM to the unit and start it and it fails with 3030 and 3040 errors.  I drop the RAM to 4096 and it will start.

The HyperV Manager shows 32GB Available, why is it not showing all my RAM?

The server is server 2008 SP2

Thank you
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Technical Lead
Commented:
Sounds like an OS limitation:  
Server2008 Standard:
  32-bit: 4GB
  64-bit: 32GB

http://www.directionsonmicrosoft.com/sample/DOMIS/update/2008/02feb/0208ws2plp_ch.htm

What server edition and architecture are you running?

Commented:
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:

http://www.experts-exchange.com/Microsoft/Applications/Virtual_Server/Q_27080005.html

Author

Commented:
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?

Author

Commented:
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?
Lee W, MVPTechnology and Business Process Advisor
SILVER EXPERT
Most Valuable Expert 2013

Commented:
Please confirm, your HOST operating system is - you are CERTAIN - Enterprise?  Or is it standard?  Enterprise should definitely see more RAM.  Standard will not.
Lee W, MVPTechnology and Business Process Advisor
SILVER EXPERT
Most Valuable Expert 2013

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

Commented:
Which edition of server?
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
GOLD EXPERT
Fellow
Expert of the Year 2017

Commented:
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

Author

Commented:
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)
Commented:
Guys "ImaCir..." already shout "Windows 2008 R2 Standard" will not use more that 32GB. no matter if you see 48GB.

http://msdn.microsoft.com/en-us/library/windows/desktop/aa366778(v=vs.85).aspx#physical_memory_limits_windows_server_2008_r2


Cheers
Svet.

Author

Commented:
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!
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
GOLD EXPERT
Fellow
Expert of the Year 2017

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

Author

Commented:
That is correct, I was using Standard instead of enterprise
ImaCircularSawTechnical Lead

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