vNVMe on Hyper-V to unlock PCIe 5.0 NVMe performance
On hosts with NVMe PCIe 5.0 (E3.S/U.2), Hyper-V guests still use virtual SCSI and leave a lot of performance on the table. We are paying for top-tier storage, yet software becomes the limiter. A virtual NVMe device that preserves checkpoints/Replica/Live Migration would align guest performance with modern hardware without forcing DDA and its operational trade-offs.NUMA Problems after In-Place Upgrade 2022 to 2025
We have updated several Hyper-V hosts with AMD Milan processors from Windows 2022 to Windows 2025 using the in-place update method. We are encountering an issue where, after starting about half of the virtual machines, the remaining ones fail to start due to a resource shortage error. The host's RAM is about 70% free. We can only get them to start by enabling the "Allow Spanning" configuration, but this reduces performance, and with so many free resources, this shouldn't be happening. Has anyone else experienced something similar? What has changed in 2025 to cause this issue? The error is: Virtual machine 'R*****2' cannot be started on this server. The virtual machine NUMA topology requirements cannot be satisfied by the server NUMA topology. Try to use the server NUMA topology, or enable NUMA spanning. (Virtual machine ID CA*****3-ED0E-4***4-A****C-E01F*********C4). Event ID: 10002 <EventRecordID>41</EventRecordID> <Correlation /> <Execution ProcessID="5524" ThreadID="8744" /> <Channel>Microsoft-Windows-Hyper-V-Compute-Admin</Channel> <Computer>HOST-JLL</Computer>26063 deduplication data corruption is still there.
From Server 2022 up to this newest 26063 build, they all have the same problem, as described here: https://techcommunity.microsoft.com/t5/windows-server-insiders/server-vnext-26040-and-server-2022-deduplication-data-corruption/m-p/4047321 I am out of energy for today and give up for today. It seems to be impossible to get Microsoft to care for actual OS bugs instead of marketing.
Allow VMs attached to internal switch on hyper-V win2k19 access Internet
Hi, I have 4 VMs attached to an internal switch with IPs 10.10.0.*, assigned 10.10.0.1 to the switch. One of the NICs on the host has the 192.168.1.70 which I shared its connection with the internal switch but I am not able to browse internet from the VMs. What can be missing? ThanksAllow Hyper-V VM attached to Internal Switch access internet and host folders
I have Created an internal switch and attached it to 4 VMs (for a lab setup) on a win2k19 hyper-V host. The hyper-V is in the my local home subnet 192.168.0.1. The 4 VMs are configured with following IPs and gateway. VM1 10.10.0.10 -DefaultGateway 10.10.0.1 VM2 10.10.0.11 -DefaultGateway 10.10.0.1 VM3 10.10.0.12 -DefaultGateway 10.10.0.1 VM4 10.10.0.13 -DefaultGateway 10.10.0.1 In the lab document, it is not indicated how/where to assign the 10.10.0..1 IP? When I check the vEthernet (Private Network), It has "DHCP" for IP and got my local DNS IP. Checking its status, I see DHCP Enabled: Yes Autoconfiguration IPv4 Address: 169.254.32.39 IPv4 Subnet Mask: 255.255.0.0 IPv4 Default Gateway: Not sure where this 169.254.... IP comes from? I tried assigning the IP 10.10.0.1 to this but it fails. In fact I need to allow VMs to access some host folders as well as internet to download some Microsoft tools. Thanks for your help
Get-ClusterExcludedAdapter cmdlet
Following link https://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterexcludedadapter?view=windowsserver2025-ps when execute Get-ClusterExcludedAdapter cmdlet with error below Get-ClusterExcludedAdapter : The term 'Get-ClusterExcludedAdapter' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At line:1 char:1 + Get-ClusterExcludedAdapter + ~~~~~~~~~~~~~~~~~~~~~~~~~~ + CategoryInfo : ObjectNotFound: (Get-ClusterExcludedAdapter:String) [], CommandNotFoundException + FullyQualifiedErrorId : CommandNotFoundException same for cmdlet Add-ClusterExcludedAdapter (https://learn.microsoft.com/en-us/powershell/module/failoverclusters/add-clusterexcludedadapter?view=windowsserver2025-ps) Does anyone know why these commands are not available?
S2D FaultDomainAwareness
We're setting up a 2 Node windows 2025 cluster with storage spaces direct After creating the pool we created two virtual disk but see the following output PS C:\WINDOWS\system32> Get-VirtualDisk | Format-List FriendlyName, Size, FaultDomainAwareness FriendlyName : ClusterPerformanceHistory Size : 25769803776 FaultDomainAwareness : StorageScaleUnit FriendlyName : S2DVOL01 Size : 10995116277760 FaultDomainAwareness : FriendlyName : S2DVOL02 Size : 10995116277760 FaultDomainAwareness : The FaultDomainAwareness is empty for the two virtual disk created on the storage pool which is configured like this PS C:\WINDOWS\system32> Get-StoragePool –FriendlyName S2D-CLHV-001-Pool | Format-List FriendlyName, Size, FaultDomainAwarenessDefault FriendlyName : S2D-CLHV-001-Pool Size : 57592038555648 FaultDomainAwarenessDefault : StorageScaleUnit is there something wrong ?Hyper-V can not be installed because virtualization support is not enabled in the BIOS
Win 2022 Datacenter as Hyper-V host Win 2022 Datacenter as Virtual Machine ... after latest Windows Updates (troublemaker KB5034439 who require resize of Recovery partition to be able to be installed successfully) ... on the VM ... is Unable to install Hyper-V Role because of the error "Hyper-V can not be installed because virtualization support is not enabled in BIOS". Very first error it was a different one and it was fixed by enabling extensions who was fixed via this commands /Hyper-V Host /Elevated PowerShell #List of VM Get-VM Get-VMProcessor -VMName <name> #Check Nested (Get-VMProcessor -VMName <name>).ExposeVirtualizationExtensions #Configure Nested Virtualization Set-VMProcessor -VMName <name> -ExposeVirtualizationExtensions $true #Disable Nested Virtualization Set-VMProcessor -VMName <name> -ExposeVirtualizationExtensions $false ... but the error "Hyper-V can not be installed because virtualization support is not enabled in the BIOS" is very tough and I not yet find any solution yet. I'm convinced that they (MS) disable Nested Support via latest Windows Update, but it is only my personal opinion. I even update firmware to the Bios of Host machine and triple check the Virtualization boxes to be enabled but since no one change it it is the same. Anyone having some idea how to Enabled Nested Virtualization on Hyper-V Host Machine ?
Untagged VLAN - Server 2025 Hyper-V
Hi, I have a strage issue and not finding a solution. Using Server 2025 with two node Hyper-V cluster. Most of the machines using VLANs which works fine. Some machines using no VLAN config. Which usually means the "Access VLAN 1" regarding our switch configuration. With Server 2019 this worked fine. With Server 2025 same NIC port, same server/NIC hardware "Untagged" VMs don't get any network connection. If I add a second NIC to the VM "Untagged" the NIC get immidiatly an IP address and has a proper connection. If I remove the first NIC, the second NIC stop working. It looks like something has changed with Server 2025 (maybe already with Server 2022). Do you have any idea what kinde of problem I have found? Thanks Jack