4 min read

Introduction

A while ago, I wrote a blog post on How to Migrate from Hyper-V Virtual Switch to Logical Switch using System Center Virtual Machine Manager 2012 R2.

This was documented based on SCVMM 2012 R2 and covered the following two key scenarios:

Scenario 1 : Migration Plan from Standard Switch to Logical Switch in Hyper-V Cluster Host.

Scenario 2: Migration Plan from Standard Switch to Logical Switch in Hyper-V Standalone Host.

Scenario 1 does NOT requires downtime, however, scenario 2 does!

Microsoft listened to our feedback and starting with System Center 2016 Virtual Machine Manager and later, the VMM team added this functionality so you can now convert any existing Hyper-V virtual switch to logical switch on the fly without any downtime for both scenarios described above.

This is very useful if you are adding an existing Hyper-V host or cluster into VMM and you need to leverage the logical switch capabilities.

In this blog post, I will share with you my experience on converting a production Hyper-V host from standard virtual switch to logical switch.

Document Your Exiting Hyper-V Virtual Switch Settings

In the first step, we need to document the existing Hyper-V virtual switch settings as follows:

The SR-IOV setting (enabled or disabled) must be the same in the logical switch as it is in the standard virtual switch. In this example, I am not using SR-IOV.

If you are using SR-IOV, then you need to make sure to enable it in VMM logical switch itself, and in at least one virtual network adapter port profile within the logical switch.

Check the bandwidth and reservation mode you are using (weight or absolute) including the minimum bandwidth percentage. In this example, I am using bandwidth reservation mode “Weight” and the minimum percentage is 30%.

If you are using Hyper-V Converged Networking, then you need to document all the vNICs on the host. In this example, I am using converged network.

You need to note the bandwidth percentage for each vNIC on the host.

You need also to note the VLANs for each vNIC.

The Teaming mode on the host must match the teaming setting in VMM logical switch Uplink Port Profile. In this example, I am using Switch Independent teaming mode and Dynamic load balancing on the host.

Finally, the VMM logical switch must be configured for the correct Network Sites (host group in VMM) to match the correct logical network for the Hyper-V host that you are converting.

If the settings in VMM logical switch that you have don’t match all the settings as described above, then you want to update or create a new logical switch that does match. If not, then the button Convert to Logical Switch… won’t illuminate whatsoever!

Convert Hyper-V Host to use VMM Logical Switch

In this example, I am using the following virtual ports for my VMM logical switch. The total bandwidth for all virtual ports are as follows:

DC Live Migration 01 = 15%

DC Live Migration 02 = 15 %

Host management = 5%

Host management DC = 5%

Hyper-V Backup Workload = 15%

Hyper-V Replica Workload = 15%

Medium bandwidth for VM traffic = 30%

The total weight bandwidth for the logical switch is 100% which match my Hyper-V host settings.

As a side note, the Logical Switch name in VMM should be the same as the Standard Hyper-V Virtual Switch name.



The Uplink Port profile and the Network Site also match my host settings including all the VLANs.

Once you update your Logical Switch in VMM to match your existing host, you need to refresh the host and wait for the job to complete in VMM.

Then go to the Virtual Switches properties for that host and click Convert to Logical Switch…

Click and confirm Convert to Logical Switch… and wait for the magic to happens in the background. Please note that the conversion will NOT interrupt network traffic.

You can also view the job in the VMM 2016 Jobs view to check if the conversion is completed successfully.

If any operation in the conversion fails, no settings will be changed, and the switch will NOT be converted.

Finally, open the Virtual Switches properties for the targeted host and confirm the changes!

Hope that helps.

Happy Switching!

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