Install CPU number 2 on a HyperV server

Question

I have a Windows 2019 server where a HyperV is installed.
When the HyperV server was installed, the physical box was with one CPU.
I have subsequently installed one more CPU in the same specification as the first CPU. I also installed the same amount of RAM for CPU 2 as CPU 1 has.
All my virtual servers have the following:

• Processor 4
• Numa Node: 1
• Sockets: 1
• Hardware Threads per core: 2

On Task Manager I can see 2 Sockets

Do I have to configure something so that I use the new CPU or does it happen automatically? Can I configure something and if so how ? :-)

Best Regards

John B

Answer 1

Hi Johnny,

Hope you're doing well.

When adding a new CPU to your Hyper-V host, there are a few considerations to ensure optimal performance and compatibility. Let's break it down:

1.Hyper-V offers a feature called “processor compatibility mode”, which allows you to move running virtual machines (VMs) or save their state between hosts with different generations of processors. By enabling this mode, you can ensure that VMs can be live migrated or saved and restored across hosts with varying processor feature sets.

2. When you add a new CPU to your Hyper-V host, Windows Server should automatically detect it and make it available for VMs. However, you might need to adjust the VM settings to take advantage of the additional CPU resources.
3. To use the new CPU, update the VM configuration:

(1) Shut down the VM.

(2) Edit its settings in Hyper-V Manager.

(3) Increase the "Number of virtual processors" to utilize the additional CPU core(s).

(4) Start the VM.

4. The "Sockets" value in Task Manager represents the total number of physical sockets on the host, not the number of CPUs assigned to the VM. It's normal to see the same number of sockets as the physical host, even if you have multiple CPUs assigned to VMs.

Best Regards,

Ian Xue

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