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System Center Virtual Machine Manager: Hosts having 0kb free memory

5:24 pm in Uncategorized by evilbart

Hey All,

One of the big issues with SCVMM 2008 for me was that the memory available on the hosts is not correct.  If you are running quite a large environment with a lot of virtual machines, it is difficult to know how many you have left.  You can of course start calculating it manually but… 😉

So here’s a screenshot of the problem

image

As you can see, all my hosts are giving zero kb free of memory.  That’s not exactly correct

Here’s how to solve this one:

On each host that has this problem, open the registry and go to the following key:

HKLM\SYSTEM\CurrentControlSet\Services\PerfOS\Parameters

If you see the key “Disable Performance Counters” then change it to 0.

Now you need to restart the WMI service on the host.  Please pay attention because it will restart other services too and you don’t want to do this during production hours…

image

After that the services are restarted, you can refresh your configuration in SCVMM and then you get the correct figures

image

 

Cheers,

Mike

Hyper-V Network Switch

10:25 pm in Uncategorized by evilbart

Hyper-V is changing the way networking works if you compare it to Virtual Server. Today I was reconfiguring my Hyper-V server and suddenly I’ve lost my RDP connection. Why did I lost my connection to the server? Well I was reconfiguring the networking settings and I wanted to add a network adapter to all my existing Virtual Machines. I created a new network which I called the external network because it was bound to my physical network interface. The moment I clicked on apply the connection was lost. I had to connect my screen and keyboard again to find out what happened, after troubleshooting a bit I saw that my NIC configuration was changed from static to DHCP address.

Why is this happening because when you create a Virtual Network with your physical NIC the way the Parent Partition connects to the network is changed.

netpic2

The parent partition is actually using a Virtual Nic witch is connected to the physical one through the Virtual Network switch. Ben Armstrong wrote an interesting post about how the networking component changed in Hyper-V

http://blogs.msdn.com/virtual_pc_guy/archive/2008/01/08/understanding-networking-with-hyper-v.aspx