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VMWare ESXi migration to Microsft Hyper-v without additional Storage

SUDHIR KUMAR SWAMY TOTA 20 Reputation points
2026-04-02T01:55:38.1166667+00:00

Hi,

We want to migrate VMWare to Microsoft Hyper-V .

Constraints and Objectives:

  1. No additional Disk space available in the SAN and can not be upgraded.
  2. We have three standalone VMWare ESXi Host each with 10 VMs.
  3. No spare additional HPE server.
  4. No Vcenter server.
  5. All the data stores are accessible from every ESXHost.
  6. Need to setup a Microsoft Hyper-V server from one of the above three ESXHosts.
  7. Need to migrate the VMs from VMWare ESXi to Microsoft Hyper-V.

How to use Windows Admin center to migrate VMWare VMs to Hyper-V without additional storage? Is there anyother method/Tool we can use ?

Thanks a lot.

Sudhir

Windows for business | Windows Server | Storage high availability | Virtualization and Hyper-V
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  1. VPHAN 28,430 Reputation points Independent Advisor
    2026-04-02T17:36:18.0633333+00:00

    SUDHIR KUMAR SWAMY TOTA

    Your proposed strategy of utilizing an external SSD is an excellent workaround to the SAN capacity constraint. By introducing this temporary hardware, you successfully create the necessary swing space to hold the newly converted virtual hard disks without fighting for storage on your existing infrastructure.

    Before you format the associated datastores, you must strictly manage your Storage Area Network connections to avoid catastrophic disruptions. Before utilizing the Windows Disk Management console to initialize and format the old VMware VMFS datastore, you must ensure that specific Logical Unit Number is completely unmapped and masked from the remaining two ESXi hosts at the SAN controller level. If the remaining ESXi hosts still have active storage paths to a volume that is suddenly formatted by Windows, it will trigger severe All Paths Down or Permanent Device Loss errors on the VMware side, potentially crashing your remaining production environment.

    When transitioning your virtual machines from the external SSD to the newly formatted SAN storage, you should avoid manually moving the folders and files. Instead, format your new SAN volume using the Resilient File System with a 64KB allocation unit size to optimize for virtualization. Once mounted to a path like E:\Hyper-V, you can use Hyper-V Manager to execute a Live Storage Migration. This built-in feature allows you to seamlessly transfer the running virtual machines from the external SSD directly to the SAN without any downtime, while automatically updating all internal path configurations and eliminating the risk of manual file copying errors.

    You should also remain mindful of the I/O limitations inherent to external drives during your testing phase. Depending on the USB interface, running multiple production workloads simultaneously from an external SSD might saturate the bus connection. If this occurs, you may notice significant performance degradation and start seeing Event ID 153 storage warnings in the Windows Event Viewer, meaning you should keep the external testing window as brief as possible before migrating the data to the SAN.

    VP

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  1. VPHAN 28,430 Reputation points Independent Advisor
    2026-04-02T02:48:48.2533333+00:00

    Hi SUDHIR KUMAR SWAMY TOTA,

    Windows Admin Center can't be used for this migration because its virtual machine migration tool strictly requires a VMware vCenter server to inventory the environment. Since you are operating with standalone ESXi hosts, native Microsoft migration utilities will be unable to connect to your infrastructure. Furthermore, migrating with absolutely zero available storage is technically impossible. Conversion tools must temporarily hold both the original VMware .vmdk virtual disk and the newly created Microsoft .vhdx virtual hard disk simultaneously during the conversion process.

    To proceed without purchasing new hardware, you must execute a rolling migration by temporarily consolidating your workloads. You will need to evacuate one of your ESXi hosts by moving its ten virtual machines to the remaining two servers, freeing up that hardware entirely. Once that host is completely empty, you can wipe the hypervisor, install Windows Server with the Hyper-V role, and connect it to your existing shared Storage Area Network. You will map the Logical Unit Numbers to the new Windows server, typically mounting them to a centralized path like C:\ClusterStorage\Volume1\ if you plan to implement Cluster Shared Volumes, or assigning them direct drive letters via Multipath I/O.

    Because you cant expand your physical disks, you must manually reclaim enough space on your shared datastores to accommodate the size of your single largest virtual machine. You can achieve this by deleting old snapshots, removing unused ISO image files, or temporarily thin-provisioning workloads. With this minimal swing space created, you can use a reputable third-party utility like the StarWind V2V Converter, which supports connecting directly to standalone ESXi hosts. You will convert one virtual machine disk into your newly freed space, verify it boots successfully on the Hyper-V host, and then permanently delete the old VMware source files to reuse that space for the next machine.

    Hope this answer brought you some useful information. If it did, please hit “accept answer”. Should you have any questions, feel free to leave a comment.

    VP

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