Replacing servers in a HYPER-V cluster and asking about processors and Live Migration.

Question

Hi. I will be replacing two servers in our HYPER-V cluster. The new two DELL R760 servers will have Intel® Xeon® Gold 6426Y processors (16 cores per processor).

I also have two DELL R750 servers in the cluster, which have Intel® Xeon® Gold 6326 processors (12 cores per processor).

Will Live Migration between these servers work without any problems? Because I previously had such a configuration that two DELL R750 servers had an Intel® Xeon® Gold 6326 processor and two DELL R740 servers had an Intel(R) Xeon(R) Gold 6126 processor and here Live migration very often did not work between these servers.....

My suspicions go in the direction that Intel(R) Xeon(R) Gold 6126 processors have 12 cores per processor and Intel® Xeon® Gold 6326 processors have 16 cores per processor and maybe this is the point that Live Migration did not work....... The previous configuration looked like this, that two servers also had different CPUs from the other two servers, but the number of cores matched (12 cores per processor) and there was no problem with Live Migration......

Thank you for your answers and help.

Best regards.

Answer 1

Hey,

Live Migration should work between different Intel CPUs, especially if CPUs are from the same generation. There are cases, when Live Migration can fail to an older CPUs. Might help with troubleshooting. https://learn.microsoft.com/en-us/troubleshoot/windows-server/virtualization/troubleshoot-live-migration-issues
More information about compatibility mode:
https://www.altaro.com/hyper-v/performance-impact-hyper-v-cpu-compatibility-mode/

Might help with cluster configuration:
https://www.starwindsoftware.com/resource-library/starwind-virtual-san-for-hyper-v-2-node-hyperconverged-scenario-with-windows-server-2016/

Cheers,

Alex Bykovskyi

StarWind Software

Note: Posts are provided “AS IS” without warranty of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

Answer 2

Hi Slawomir,

Thanks for your post. From official recommendation, Hyper-V cluster needs to keep all the nodes as same, including the CPU. For better clarification, you can select any of the Validate Configuration items.

One is found on the context menu of the Failover Cluster Manager root node in the left pane and another is in the center pane when that root node is selected. Once you’ve done so, the Validate a Configuration Wizard appears. The wizard contain the following series of screens:

1. The first page of the dialog is merely informational. You can optionally select to never have that page appear again if you like. When ready, click Next.
2. The second page asks you to select the hosts or the cluster to be validated. If a host is already part of a cluster, selecting it will automatically include all nodes of the cluster. You can use the Browse button to scan Active Directory for computer names. You can also just type the short name, fully-qualified domain name, or IP address of a computer and click Add to have Failover Cluster Manager search for it. Once all hosts to be validated for a single cluster have been selected, press Next.
3. The following screen provides two choices. The first specifies that you wish to run all available tests. This is the most thorough, and this is the validation that Microsoft expects for complete support. However, some tests do require shared storage to be taken offline temporarily, so this may not be appropriate for an existing cluster. The second option allows you to specify a subset of available tests.
4. If you opted to run only selected tests, the next screen will ask you to specify which tests to run. You can click the plus icon next to any top-level item to see sub-tests for that category. Deselect the Storage category if you are working on a live cluster and interruption is not acceptable.
5. After test selection, you’ll be taken to a confirmation screen that lists the selected nodes and tests that will be run on them. Verify that all is as expected and click Next when ready.
6. The tests will begin and their progress will be displayed. The overall test battery can take quite some time to complete.
7. When the tests complete, you will automatically be brought to the Summary page. Here, you can click View Report to see a detailed list of all tests and their outcomes. You can check the box Create the cluster now using the validated nodes in order to start the cluster creation wizard immediately upon clicking Finish.

Best Regards,

Ian Xue

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