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nmdange2 / HyperV_DSC

A set of sample DSC scripts for configuring Hyper-V hosts, Scale-Out File Servers. Can be used for Storage Spaces Direct or any other back-end storage.
MIT License
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Networking configuration (VMSwitch) #1

Open jaromirk opened 5 years ago

jaromirk commented 5 years ago

https://github.com/nmdange2/HyperV_DSC/blob/master/DSC/HyperVFabricSettings.ps1#L697-L721

You want to enable SR-IOV. You should not use weight when using RDMA enabled vNICs and also you might want to have native VLAN on mgmt NIC.

nmdange2 commented 5 years ago

So I've been using SCVMM for deploying logical switches for quite some time, even before RDMA vNICs were possible. It seems like SCVMM tends to encourage use of minimum bandwidth weight based on the default settings of the port profiles. I believe the minimum bandwidth weight and maximum bandwidth wouldn't apply to RDMA traffic, but I do use them to control the bandwidth of the VMs themselves. It's not so clear to me how you would manage VM bandwidth without using minimum bandwidth weight and maximum bandwidth settings.

I generally don't enable SR-IOV on the switch unless I have VMs that I want to use with SR-IOV. In most cases, I don't do that because the VMs aren't trusted. I don't think SR-IOV is required on the VMSwitch if you are only using RDMA vNICs on the management OS.

I do need to add setting the VLAN on the management NIC, right now I haven't included that in the DSC settings because it's being done through SCVMM. It also doesn't help that there's both VMNetworkAdapterVlan and VMNetworkAdapterIsolationSettings.

jaromirk commented 5 years ago

Did you see SCVMM scenarios in WSLab? (Bare metal deployment, VMM2019... )... I'm using correct port profiles...

nmdange2 commented 5 years ago

So I looked through the scenarios in WSLab. I can see that you set the MinBandwidth mode to Absolute (or None if enabling SRIOV). I also see that on the port profile for the virtual machines, you are not setting any value for minimum bandwidth and maximum bandwidth.

So in my setup I have three port profiles for virtual machines (I think these came with VMM by default, but I may have tweaked the settings from their original values)

Low Bandwidth - minimum bandwidth weight set to 1, maximum bandwidth set to 2gbps Medium Bandwidth - minimum bandwidth weight set to 3, maximum bandwidth set to 6gbps High Bandwidth - minimum bandwidth weight set to 5, maximum bandwidth not set (unlimited)

I use those port profiles to ensure test VMs get lower bandwidth and critical VMs get the most bandwidth. I've been using these port profiles since 2012 so the question is, is that still supported when used in conjunction with RDMA vNICs on the host, or is there some other way to achieve what I'm doing?