BLOG: Determine and modernize Filesystem Deduplication
Version history - 1.6 Added references / links - 1.5 Added insights from Steven Ekren. Many thanks! / Added ReFS Docs link and added clarification about drawbacks. - 1.4 revised script so ReFS volumes with classic dedup will be identified, added more eligibly checks and error handling - 1.3 added point #4 in migration guidance - 1.2 revised script - 1.1 formatting This blog explains the two Windows deduplication modes classic Windows Data Deduplication (ReFS or NTFS) and ReFS Deduplication (ReFS). It covers how they differ, why you should consider upgrading to Windows Server 2025 to leverage the new ReFS dedup engine, and clear warnings about scenarios where ReFS is not recommended. Practical migration guidance and detection commands are included. Differences between classic dedup and ReFS dedup File system: Classic dedup runs on NTFS or ReFS; ReFS dedup runs on ReFS and Windows Server 2025 or later, only. Implementation: They are separate engines with different metadata formats and management cmdlets. Management: Classic dedup uses the Dedup PowerShell module (Get‑DedupVolume, Start‑DedupJob, Disable‑DedupVolume). ReFS dedup uses its own ReFS dedup cmdlets (Get‑ReFSDedupStatus, Enable‑ReFSDedup). Conversion: There is no in‑place conversion between the two; metadata and chunk formats are incompatible. Improvements: the new in-line ReFS Deduplication leverages the advantages of ReFS files system. This makes deduplication more efficient and less CPU intensive. The new ReFS Deduplication can also compress data in-line using L1Z algorithm. This makes it up to par with enterprise solutions, often found in SAN storage or Linux appliances. Compression needs to be set per volume, and optional. Edit: Steven Ekren, a former Senior Product Manager for Hyper-V shared valuable insights on how both engines operate in a comment on LinkedIn: [...] the basic conceptual difference between WS Deduplication and ReFS deduplication is that the Windows Server [dedup] version takes the duplicate file data and moves it to a repository and puts a reparse point in the file system from each point that references the data. This involves data movement and therefore not recommended for workloads that are changing it's data often, but best for more static data like documents and picture/videos. ReFS is a file system that uses links natively for all the objects so leaving the data in place and managing the links is much more efficient and doesn't involve the data copy and managing a repository. Effectively it's built into the file system. As the blog notes, there are some situations not recommended for this version of dedupe, but generally it's lower performance and storage I/O impact. Why upgrade to Windows Server 2025 Improved version of ReFS Filesystem Improved ReFS in-line deduplication + optional L1Z compression: Server 2025 includes enhancements to ReFS dedup performance, scalability, and integration with modern storage features. Support and fixes: Windows Server 2016 and 2019 are past mainstream support, increasing the likelihood of costly support cases and delayed fixes; upgrading reduces operational risk and ensures access to ongoing improvements. Future compatibility: Newer OS releases receive optimizations and bug fixes for ReFS and dedup scenarios that older releases will not. SMB compression: for reasonably faster data transfer at minimal CPU when transferring data through the networks. Feature and security related improvements refer to availabile Microsoft Windows Server 2025 Summit content on techcommunity.microsoft.com Scenarios where ReFS is not recommended ReFS on SAN in clustered CSV environments: Avoid placing ReFS dedup on top of SAN‑backed Cluster Shared Volumes (CSVFS) in production clusters; clustered SAN/CSV scenarios causing severe performance issues in practice. Please refer to the ReFS documentation. (personal opinion and experience, not endorsed by Microsoft): Many small, fast‑changing files: Workloads with frequent small writes, such as user profiles, folder redirection of AppData folders, or applications that churn small config files (for example, Lotus Notes config files) can cause locks, performance degradation, or unexpected behavior on ReFS. Exclude these disks from dedup or keep them on NTFS. Note: Restrictions on high churn rate, like lockups or high RAM consumption, deadlocks / BSOD might have been addressed in Windows Server 2025 and the ReFS Dedup, see comment of Steven Ekren. Improving reliability and performance is a top goal for ReFS, to improve the adoption and feature parity with NTFS. For information about feature parity please refer to the ReFS documentation. Migration guidance The following instructions describe a high level and supported migration path from Windows deduplication using the NTFS file system to native ReFS Deduplication. Note: Step #3, data migration is not required when already using ReFS with Data Deduplication. In this case it's enough to execute step #1 and #2. Note: Validate on non‑production data first. Plan for rehydration time and network/storage throughput. Ensure backups are current before starting. Make sure to have a full backup before upgrading Server OS or making changes. 1. Disable classic dedup on the NTFS source: Disable-DedupVolume -Volume YourDriveLetter: 2. Rehydrate (un‑deduplicate) the data: Start-DedupJob -Volume YourDriveLetter: -Type Unoptimization 3. Copy or move data to a ReFS volume (new target): For straightforward NTFS→ReFS copies, robocopy is recommended. A GUI and job based alternative to this is the File Server Migration Feature (uses robocopy) in Windows Admin Center. For complex scenarios, open files long path names very large datasets (< 5 TB) or many small files restructuring, GUI (including Windows Server Core) automation, improved logging cloud/hybrid migrations I recommend the usage of GS RichCopy Enterprise by GuruSquad for higher speed (up to 40%) and reliability, compared to robocopy. 4. Optionally remove the Windows Server feature When there is no old deduplication in use consider to remove the feature. Your advantages of doing so: removes an unneccessary service. removes the file system filter driver for dedup, which causes performance impacts, even when not in use. removes the PowerShell commandlets for the old dedup, so they cannot mistakenly used by existing scripts, unaware admins etc. When migrating files over network: SMB compression: consider both source and target run Windows Server 2025 and leverage SMB compression. SMB Compression is available in Microsoft xcopy, Microsoft robocopy and Gurusquad GScopy Enterprise. Balancing and Teaming with SMB: SMB does not require LFBO or SET Teaming. It automagically detects network links and actively balances on its own on Windows Server 2016 and later. Using teaming, depending the configuration, can negatively affect transfer speed. Quick detection and diagnostic commands Check file systems: Get-Volume | Select DriveLetter, FileSystem Check classic dedup feature: Get-WindowsFeature -Name FS-Data-Deduplication Get-DedupVolume Get-DedupStatus Check ReFS dedup: Get-Command -Module Microsoft.ReFsDedup.Commands Get-ReFSDedupStatus -Volume YourDriveLetter: Diagnostic script to detect both: <# .SYNOPSIS Detects classic NTFS Data Deduplication and ReFS Deduplication across local volumes. .DESCRIPTION - Reports NTFS volumes with classic Data Dedup enabled. - Lists ReFS volumes present on the host. - If the ReFS dedup cmdlet exists AND OS build >= 26100, checks ReFS dedup status per ReFS volume. - Color coding: * Classic dedup enabled → Yellow * Classic dedup not enabled → Cyan * ReFS dedup enabled → Green * ReFS dedup not enabled → Cyan .NOTES Version: 1.7 Author: Karl Wester-Ebbinghaus + Copilot Requirements: Elevated PowerShell session, PowerShell 5.1 or newer Supported OS: Windows Server 2025, Azure Stack HCI 24H2 or newer Unsupported OS: Windows 10, Windows 11 (script terminates) #> #region Initialization Write-Verbose "Initializing variables and environment..." $Volumes = $null $Volume = $null $DedupVolumesList = $null $DedupReFSVolumesList = $null $DedupReFSVolumesListLetters = $null $DedupReFSStatus = $null $refsCmd = $null $OSBuild = $null $runReFSDedupChecks = $null #endregion Initialization #region Volume Discovery Clear-Host Write-Verbose "Querying NTFS and ReFS volumes..." $Volumes = Get-Volume | Where-Object FileSystem -in 'NTFS','ReFS' #endregion Volume Discovery #region ReFS Dedup Cmdlet, OS Build and OS SKU Detection Write-Verbose "Checking for ReFS deduplication cmdlet..." $refsCmd = Get-Command -Name Get-ReFSDedupStatus -ErrorAction SilentlyContinue Write-Verbose "Reading OS build number..." try { $OSBuild = [int](Get-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' -Name CurrentBuildNumber).CurrentBuildNumber } catch { Write-Verbose "Registry read for OS build failed. Falling back to Environment OSVersion." $OSBuild = [int][Environment]::OSVersion.Version.Build } # end try/catch for OS build detection Write-Verbose "Checking OS InstallationType and EditionID..." $CurrentVersionKey = Get-ItemProperty -Path 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' $InstallationType = $CurrentVersionKey.InstallationType # "Client" or "Server" $EditionID = $CurrentVersionKey.EditionID # e.g. "AzureStackHCI", "ServerStandard", etc. Write-Verbose "Detected InstallationType: $InstallationType" Write-Verbose "Detected EditionID: $EditionID" Write-Verbose "Detected OSBuild: $OSBuild" # Block Windows 10/11 (Client OS) if ($InstallationType -eq 'Client') { Write-Error "Unsupported OS detected: Windows Client (Windows 10/11). Only Windows Server or Azure Stack HCI are supported. Script will terminate." exit } # Allow Azure Stack HCI explicitly if ($EditionID -eq 'AzureStackHCI') { Write-Verbose "Azure Stack HCI detected. Supported platform." } else { # Must be Windows Server if ($InstallationType -ne 'Server') { Write-Error "Unsupported OS detected. Only Windows Server or Azure Stack HCI are supported. Script will terminate." exit } Write-Verbose "Windows Server detected (EditionID: $EditionID). Supported platform." } Write-Verbose "Evaluating ReFS dedup eligibility based on cmdlet presence and build >= 26100..." $runReFSDedupChecks = $false if ($refsCmd -and ($OSBuild -ge 26100)) { $runReFSDedupChecks = $true Write-Verbose "ReFS dedup checks ENABLED (cmdlet present and OS build >= 26100)." } else { Write-Verbose "ReFS dedup checks DISABLED (cmdlet missing or OS build < 26100)." } #endregion ReFS Dedup Cmdlet, OS Build and OS SKU Detection #region Main Loop foreach ($Volume in $Volumes) { # begin foreach volume loop Write-Host "Volume $($Volume.DriveLetter): ($($Volume.FileSystem))" Write-Verbose "Processing volume $($Volume.DriveLetter)..." #region Classic Dedup + ReFS Volume Listing if ($Volume.FileSystem -eq 'NTFS' -or $Volume.FileSystem -eq 'ReFS') { Write-Verbose "Checking classic deduplication status for volume $($Volume.DriveLetter)..." $DedupVolumesList = Get-DedupVolume -Volume $Volume.DriveLetter -ErrorAction SilentlyContinue if ($DedupVolumesList) { Write-Host " → Classic Data Dedup ENABLED on $($Volume.DriveLetter), $($Volume.FileSystem)" -ForegroundColor Yellow } else { Write-Host " → Classic Data Dedup NOT enabled on $($Volume.DriveLetter),$($Volume.FileSystem)" -ForegroundColor Cyan } # end if classic dedup enabled Write-Verbose "Listing ReFS volumes on host..." $DedupReFSVolumesList = Get-Volume | Where-Object FileSystem -eq 'ReFS' if ($DedupReFSVolumesList) { $DedupReFSVolumesListLetters = ($DedupReFSVolumesList | ForEach-Object { $_.DriveLetter }) -join ',' Write-Host " → ReFS volumes present on host: $DedupReFSVolumesListLetters" } else { Write-Host " → No ReFS volumes detected on host" } # end if ReFS volumes present } # end NTFS/ReFS block #endregion Classic Dedup + ReFS Volume Listing #region ReFS Dedup Status if ($Volume.FileSystem -eq 'ReFS') { if ($runReFSDedupChecks) { Write-Verbose "Checking ReFS deduplication status for volume $($Volume.DriveLetter)..." $DedupReFSStatus = Get-ReFSDedupStatus -Volume $Volume.DriveLetter -ErrorAction SilentlyContinue if ($DedupReFSStatus) { Write-Host " → ReFS Dedup ENABLED on $($Volume.DriveLetter), $($Volume.FileSystem)" -ForegroundColor Green } else { Write-Host " → ReFS Dedup NOT enabled on $($Volume.DriveLetter), $($Volume.FileSystem)" -ForegroundColor Cyan } # end if ReFS dedup enabled } else { if (-not $refsCmd) { Write-Error " → Skipping ReFS dedup check: Get-ReFSDedupStatus cmdlet not present" -ForegroundColor Cyan } else { Write-Error " → Skipping ReFS dedup check: OS build $OSBuild < required 26100" -ForegroundColor Cyan } # end reason for skipping ReFS dedup check } # end if runReFSDedupChecks } # end if ReFS filesystem block #endregion ReFS Dedup Status Write-Host "" } # end foreach volume loop #endregion Main Loop #region End Write-Verbose "Script completed." #endregion End Recommendations and next steps Inventory: Identify volumes using NTFS dedup and ReFS dedup, and map workloads that create many small or rapidly changing files. Plan: Schedule rehydration and migration windows; test ReFS dedup on representative datasets. Upgrade: Prioritize upgrading servers still on 2016/2019 (End of Mainstream Support) to reduce support risk and gain the latest ReFS dedup improvements. Kindly consider reading my Windows Server Installation Guidance and Windows Server Upgrade Guidance Exclude: Keep user profiles, AppData, and other high‑churn small‑file paths off ReFS dedup or on NTFS. Consider ReFS Dedup with Compression: Enable compression optionally. Mind ReFS dedup compression is not the same as compress files integration in File Explorer or File Explorer properties (Windows 9x). It's transparent to the application Make smart decisions: Avoid using dedup when the dataset is changing fast or your dedup + compression rate is below 20%. Usually you can expect 40% or more savings, and up to 80% in specific use cases like VDI VHDX with ReFS Dedup + Compression. Plan your dedup jobs: Ensure of making use of the planning features for dedup jobs through PowerShell or Windows Admin Center (WAC) when using ReFS dedup on more than one volume per Server. Otherwise they might all run at the same time and impact your storage performance (esp. spinning rust) and consumption of RAM and CPU. Share and Educate: Inform your infrastructure team about the changes so they avoid using the traditional dedup on ReFS. Related blogposts: https://splitbrain.com/windows-data-deduplication-vs-refs-deduplication/ , Thanks Darryl van der Peijl and team. https://www.veeam.com/kb2023 Veeam best practices about Windows Deduplication and ReFS Deduplication.A CISO's Guide to Securing AI - Securing AI for Federal, DIB, and DoW Entities
Artificial Intelligence (AI) is rapidly reshaping federal missions, defense operations, and critical infrastructure. From intelligence analysis to logistics and cyber defense, AI’s transformative power is undeniable. Yet, with great power comes great responsibility and risk.
WSUS changing Update Source on its own
We have 2 WSUS Servers and ConfigMgr. A week ago, one of the WSUS servers began changing the Update Source on its own, no changes had been made. It began pointing to the ConfigMgr and when changed back to use MS Update, shortly after checking again it reverted back to use ConfigMgr. Checked all Events, checked the SQL SUSDB for the WSUS server however there was no information related to this action. Any ideas where I can look next ? Thank youISSUE: Microsoft ADK b25217 or earlier, VAMT 3.1 has issues with Windows Server 2019 / 2022
Affected Products: Windows ADK VAMT 3.x - W11 version 22H2 Windows ADK VAMT 3.x - W11 version 21H2 Windows ADK VAMT 3.x - W10 version 21H2 Windows ADK VAMT 3.x - WS2022 version Windows ADK VAMT 3.x - current preview 1. VAMT 3.1 has the issue that the Windows Server 2022 is still named Windows Server 2021 in the configuration. Introduced with ADK Windows 11 ADK 21H2 / Windows Server 2022 ADK Problem: 2. GVLK for Windows Server 2019 Datacenter or Standard are no longer accepted. Introduced with ADK Windows 11 ADK 22H2 (eventually previous versions) Problem: WS 2019 Standard + Datacenter generic keys can no longer be added to VAMT database. Other product keys seem unaffected. error: GVLK Key source https://learn.microsoft.com/windows-server/get-started/kms-client-activation-keys Thank you for flagging this to the team, it has been discussed in other topics, but I hope the next release of ADK will provide a fix (DB connection issue, is already fixed). TYVM in advance.Automating Windows Server Licensing Benefits with Azure Arc Policy
Introduction: Managing Windows Server benefits licensing across hybrid environments can be challenging. Azure Arc combined with Azure Policy simplifies this by automatically enforcing licensing compliance. This blog explains how the provided policy works and how to deploy it. Why implement this policy? Automating Windows Server Licensing Benefits with Azure Arc Policy ensures that all eligible machines are seamlessly enabled for essential management services, including Azure Update Manager, Best Practice Assessment, Change Tracking, Inventory, and Windows Admin Center integration. For organizations managing hundreds or thousands of servers, manual enablement can be time-consuming and error prone. This policy continuously monitors your environment, automatically identifying newly added machines and highlighting those missing the required benefits, so you can maintain compliance and streamline operations at scale This learn document detail the benefits available when Windows Server is connected via Azure Arc, especially for machines with Software Assurance or subscription licenses: https://learn.microsoft.com/en-us/azure/azure-arc/servers/windows-server-management-overview?tabs=portal Note – Ensure that your organization has the proper Software Assurance Benefits to cover the machines that are being assigned. Please reference this link for billing information Windows Server Management enabled by Azure Arc - Azure Arc | Microsoft Learn "Customers need to explicitly attest for their Azure Arc-enabled servers or enroll in Windows Server pay-as-you-go to be exempt from billing for these services. Eligibility isn't inferred directly from the enablement to Azure Arc. Eligibility is not inferred from licensing status for the Azure Arc-enabled SQL Server instances that may be connected to an Azure Arc-enabled." Policy Purpose and Logic The policy ensures Arc-enabled Windows Servers are licensed correctly. It evaluates machines based on OS type, license status, and conditions for Software Assurance or Pay-As-You-Go. If compliance is missing, a remediation policy deploys the appropriate license profile. Key Conditions Applies to resources of type Microsoft.HybridCompute/machines with osType = windows. Checks if licenseProfile.licenseStatus equals Licensed. Uses existenceCondition to determine if the machine should have SA or PAYG licensing based on osSku and licenseChannel. Deployment Details The policy uses DeployIfNotExists effect. It deploys licenseProfiles under the Arc machine resource. Two scenarios are handled: Pay-As-You-Go: If licenseChannel contains 'PGS', productProfile.subscriptionStatus is set to Enabled. Software Assurance: If licenseChannel does not contain 'PGS', softwareAssuranceCustomer is set to true. The Policy The policy is located in GitHub (Link) and AzPolicyAdvertiser (Link). Download the policy files to be used in the following steps. Policy Description For 2025 server, if license type is Pay-as-you-go, then this will check the Pay-as-you-go box in license menu. If 2025 and not Pay-as-you-go license or not 2025 server then check Software Assurance box. This policy only checks Windows Server resources and will NOT check unlicensed servers How to Deploy the Policy After downloading the policy file, use Az PowerShell to create and assign the policy: #Create policy definition New-AzPolicyDefinition ` -Name "activate-azure-benefits-for-windows-arc-machines" ` -DisplayName "Activate Azure Benefits for Windows Arc Machines" ` -Policy 'azurepolicy.json' ` -ManagementGroupName "<MyManagementGroup>" ` -Mode Indexed #Assign policy definition $Policy = Get-AzPolicyDefinition -Name 'activate-azure-benefits-for-windows-arc-machines' -ManagementGroupName "<ScopeOfDefinitionCreation>" New-AzPolicyAssignment ` -Name "activate-arc-benefits" ` -DisplayName "Activate Azure Benefits for Windows Arc Machines" ` -PolicyDefinition $Policy ` -Scope "/providers/Microsoft.Management/managementGroups/<MyManagementGroup>" ` -Location 'eastus' ` -IdentityType 'SystemAssigned' # Optional use subscriptions instead of management groups. # or "/subscriptions/<SubscriptionId>" You can also copy and paste the contents of the policy into the portal or use a policy-as-code solution of your choice. Compliance The compliance blade of the Azure Policy will show the machines that do not abide by the policy definition. In this example many of the machines are not enabled for the Windows Server Benefits. The next step will be to use remediation tasks to enable these machines. On the Policy Remediation blade, you can initiate a remediation task to add the machines to enable the Azure Arc Benefits. Choose between the two radio button options for remediating all the selected locations, a single location, or select specific resources to remediate. When the Remediate button is pressed, a task is summitted and a notification will be displaced when the task is completed. The process may take some time and a status of In Progress will be displayed until the status changes to Complete. After this is completed go back and look at the Azure Arc Benefits – Windows Server Blade and you will see the machines activated. Note on Pay-as-you-go enablement When a Windows machine is deployed using Pay-as-you-go, as an example a new Windows Server 2025 machine, the status of the license after creation will be “Unlicensed” as shown below. The policy is not evaluating Unlicensed machines. The machine will need to have the Pay-as-you-go with Azure check box checked at least one time to “License” the machine. After the machine is Licensed the License details will show: Now if the machine would have the benefits removed in the future by unchecking the box, the machine will be audited with the policy. As an example, the Arc machine would show that the License type is Pay-as-you-go, Licensed, Disabled (for the Azure Benefits). Summary This policy automates Windows Server licensing for Arc-enabled machines. It ensures compliance by deploying license profiles for Software Assurance or Pay-As-You-Go scenarios. Deploying this policy reduces manual effort and enforces consistent licensing across your hybrid environment.Microsoft Clearinghouse server connection issues + phone line is dead end
We see a rising number of customers having issues installing or reinstalling their RDS Licenses via automatic connection. According to volume licensing support reinstalling licensing should not work this way any longer and requires customers to contact the RDS activation hotline which is +49 800 5077777 for Germany. If you dial through the menu and reach the RDS Licensing support, for weeks it is not possible to get through speaking with any agent. Instead the phone computer asks for your phone number and to enter it via your phone (DTMF). Whatever the way you enter a number like +492212343434 or 02212343434 it ends up that the voice computer says the number cannot be recognized. I guess that the Microsoft Clearinghouse server has issues with TLS 1.2 and some ciphers but we cannot pin it down even with the networking guys. Here are some possible messages: Customer A: Cannot install licenses, the server is correctly activated and can also be reactived successfully Customer B: Cannot install licenses, server ist correctly activated but can only be reactivated via web. Interestingly activating or reactivating the RDS CAL Server itself works fine on some customers On Other customers even this is not successful anymore due to connection issues. I began to see this last year when customers began to use Windows Server 2019 RDS CAL Servers, while Windows Server 2016 and 2012 R2 were unaffected. We have tried to setup a fresh Windows Server but no help. So 3 things causing a combined issue and blocker: - the RDS CAL phone support is unavailable in Germany - Automatic activation installing new licenses does not work (but is required for RDS via CSP) - Automatic activation re-installing already activated licenses does no longer work according to VL Support as - Automatic activation for Activation / Reactivation of a Server does not work anymore for some customers due to connection issuesAnnouncing General Availability for Azure Resource Graph (ARG) GET/LIST API
ARG GET/LIST API delivers 10X higher throttling quotas to callers compared to ARG query unlocking a more scalable, resilient way to perform resource lookups in Azure. ARG GET/LIST API is a new platform capability within Azure Resource Graph that provides a high-performance experience for both Point GET and collection GET requests. A key advantage of this capability is its ability to significantly reduce READ throttling for high volume calls efficiently. This is made possible through intelligent control plane routing based on a query parameter controlled by the caller. When a specific query parameter is included, requests are automatically directed to this optimized ARG GET/LIST backend. When the parameter is omitted, requests flow to the Resource provider —ensuring flexibility and backward compatibility. What Challenge Are We Addressing? Azure Read Throttling is a significant challenge for many customers. When services hit throttling limits, applications may experience performance degradation, elevated latency, or even failed requests—issues that can disrupt critical workloads and customer operations. The ARG GET/LIST API is designed to directly address this problem. By routing GET and LIST calls through Azure Resource Graph’s scalable indexing infrastructure and intelligent control-plane routing, it dramatically reduces the likelihood of read throttling. Best of all, it follows the ARM control plane GET APIs request response contract, allowing you to benefit from improved performance and reliability with minimal effort, appending the flag “useResourceGraph=true”. When to use Azure Resource Graph (ARG) GET/LIST API The ARG GET/LIST API is designed for scenarios where you need to retrieve a single resource by its ID or list resources of the same type within a defined scope—whether that's a subscription, resource group, or parent resource. You should consider using the ARG GET/LIST API if your service fits into one or more of the following categories: High Volume of GET Calls Within a Single Scope: Your service issues a large number of GET requests targeting resources within a single subscription or resource group, without the need for cross-subscription queries, complex filters, or joins. Risk of Throttling or Quota Competition: Your service produces a high volume of requests and may encounter issues such as:: Experience throttling during sudden traffic spikes. Quota competition, where other workloads in the same subscription consume shared quota limits, causing your service to be throttled. Bursty traffic patterns, where large volume of GET requests are issued within a short time window, increasing the chance of throttling. Need for High Availability and Faster Performance: Your service depends on consistent; low-latency GET operations for either single-resource lookups or listing resources within a specific scope Note: The ARG GET/LIST API is currently supported only for resources in the resources and computeresources tables. Using the ARG GET/LIST API To get started with the ARG GET/LIST API, begin by assessing whether your scenario aligns with the recommended calling patterns and throttling considerations described earlier. Once confirmed, simply append the parameter &useResourceGraph=true to your eligible GET/LIST API calls. This flag routes your request through the Azure Resource Graph GET/LIST API backend, allowing you to take advantage of its optimized performance and query efficiency. No calls will route to ARG GET/LIST backend automatically. The switch is entirely in the user’s control—the call will route to ARG GET/LIST API only when you explicitly include the useResourceGraph=true parameter in your request. Follow the ARG GET/LIST API contract here - Azure Resource Graph GET/LIST API Guidance - Azure Resource Graph | Microsoft Learn Let’s walk through a simple example of retrieving a Virtual Machine (VM) along with its InstanceView through ARG Query vs. ARM API vs. ARG GET/LIST API to show the difference in the calling experience. Using an ARG Query (via ARG Explorer) In ARG Explorer, you can use Kusto Query Language (KQL) to query resources. A sample query to retrieve a specific VM looks like this: Resources | where type =~ 'microsoft.compute/virtualmachines' | where id =~ '/subscriptions/{subscriptionId}/resourceGroups/{resourceGroup}/providers/microsoft.compute/virtualmachines/{vm}' This query filters the Resource Graph index to return the VM resource. Using the ARM (Compute RP) API The equivalent ARM API call to retrieve the VM with InstanceView is: GET https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroup}/providers/microsoft.compute/virtualmachines/{vm}?api-version=2024-07-01&$expand=instanceView This hits the Compute Resource Provider, pulls the VM state, and expands the instanceView section. Using the ARG GET/LIST API ARG GET/LIST APIs that follow the same request structure as ARM—but with an additional flag that routes the call through ARG: GET https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroup}/providers/microsoft.compute/virtualmachines/{vm}?api-version=2024-07-01&$expand=instanceView&useResourceGraph=true The important distinction here is the useResourceGraph=true parameter, which routes the call through ARM to serve the response through ARG’s GET/LIST backend. Sample Response - You can find more examples in our documentation - Azure Resource Graph GET/LIST API Guidance - Azure Resource Graph | Microsoft Learn Video Walkthrough Increase Throttling Quota via Azure Resource Graph Learn More Azure Resource Graph GET/LIST API Overview Known Limitations Frequently Asked Questions Share Your Feedback For questions and feedback, you can reach us at Azure Resource Graph team Share Product feedback and ideas with us at Azure Governance · Community Happy Querying!
Volume Activation role questions
We have a DC, running Server 2016 to decommission (call it old server). One of the roles it had was Volume Activation (VA). This is Active Directory based and the keys AD holds are both for clients (Win11) and servers (2016/19/22/25). I have removed the VA role from the server and tested with a server which I added to the domain and the OS activated successfully, so it looks like it is working. I noticed the _vlmcs SRV DNS record was not deleted and is still pointing to the old server. Since the old server is no longer having the VA role, is it safe to delete the DNS record for the _vlmcs SRV record? What else do I need to take into account? Thanks in advance
