SCVMM VMWare to Hyper-V Conversion Overview

Overview

SCVMM (System Center Virtual Machine Manager) can convert VMware VMs (VMDK) into Hyper-V VMs (VHDX) through a V2V (Virtual-to-Virtual) conversion. It uses a library server as an intermediate storage and performs format conversion during the copy process.

 

Prerequisites

1. Environment Prep

·         SCVMM must be installed and functioning.

·         Add vCenter Server to SCVMM.

·         Ensure the VMware VM tools are installed in the guest OS.

·         SCVMM needs credentials to vCenter with read permissions.

·         Create a Run As account for vCenter authentication.

·         Target Hyper-V hosts must be available and managed in SCVMM.

2. Ports and Protocols

·         SMB (TCP 445), WinRM (TCP 5985), BITS, and HTTPS (TCP 443) must be open between:

o    SCVMM ↔ VMware ESXi/vCenter

o    SCVMM ↔ Hyper-V hosts

o    SCVMM ↔ Library server

 

Step-by-Step SCVMM V2V Conversion Process

Step 1: Add VMware Environment

1.      Open SCVMM console.

2.      Go to "Fabric" workspace.

3.      Under "Infrastructure" > "vCenter Servers", right-click and choose "Add VMware vCenter Server".

4.      Enter vCenter address and credentials (via Run As account).

5.      Confirm discovery of VMware VMs and clusters.

 

 

Step 2: Prepare Conversion Target

1.      Ensure a Hyper-V host is in a valid host group.

2.      Prepare network sites, clouds, and storage classifications if needed.

 

Step 3: Initiate Conversion

1.      Go to "VMs and Services" > right-click "VMware VM" > choose "Convert Virtual Machine".

2.      Wizard opens:

o    Select source VMware VM.

o    Choose a target Hyper-V host or host group.

o    Set destination path for VHDX.

o    Map VM hardware (CPU, RAM, NICs, etc.).

o    Select virtual network (match to Hyper-V network).

o    Choose disk format: VHDX, and dynamic or fixed.

Tip: Choose dynamic VHDX to save space unless fixed-size is required for performance.

 

Step 4: Job Execution

·         SCVMM:

o    Copies the VMDK to a library server.

o    Converts VMDK → VHDX.

o    Places the new VHDX on the Hyper-V target.

o    Creates and registers the new VM on the Hyper-V host.

·         Monitor progress under "Jobs" in the SCVMM console.

 

Step 5: Post-Conversion Validation

·         Power on the VM.

·         Uninstall VMware Tools manually.

·         Install Hyper-V Integration Services (if not already present; note that modern Windows VMs already include this).

·         Validate network, storage, and service functionality.

 

 

Notes & Best Practices

Practice	Recommendation
Cold conversion	Recommended for consistency. Shut down VM before converting.
Clean guest OS	Remove unused files/apps before conversion to reduce size.
Library server tuning	Use SSD or NVMe-based storage for faster conversions.
No pass-through disks	SCVMM cannot convert VMs with RDMs or pass-through disks.
No snapshots	Convert only the current state of the VM.
Encryption	VMs with encrypted disks may fail to convert.

 

 

 

Proactive Approach Converting VMWare to Hyper-V VM’s

When using SCVMM (System Center Virtual Machine Manager) to convert VMware VMs to Hyper-V, there are a number of common issues you might encounter—especially when dealing with guest OS configurations, drivers, and disk formats. Below is a categorized list of real-world problems, their causes, and how to mitigate them.

 

Common Issues with SCVMM Conversions (VMware → Hyper-V)

1. VM Fails to Boot on Hyper-V

Problem	Cause	Fix
Black screen or boot loop	VMware bootloader/BIOS mismatch (e.g., EFI to BIOS)	Match firmware settings during conversion (BIOS vs. UEFI)
INACCESSIBLE_BOOT_DEVICE	Missing IDE/SCSI drivers or boot device mismatch	Inject Hyper-V-compatible storage drivers manually or convert to VHDX with correct controller
Boot device not found	Wrong boot order or missing boot partition	Check VM settings and disk layout post-conversion

 

2. Disk Conversion Issues

Problem	Cause	Fix
Disk size mismatch	Thin-provisioned disks misreported	Use RVTools to verify actual used size before conversion
Pass-through or RDM disks not migrated	SCVMM does not support these types	Remove or convert them to VMDK files first
Dynamic VHDX too large	Source disk is mostly empty but still copied entirely	Clean up VM prior to conversion, or use tools like StarWind V2V for leaner conversions

 

 

3. Hardware Compatibility Errors

Problem	Cause	Fix
VMware tools interfere with integration services	Conflicting drivers/services	Uninstall VMware Tools before or immediately after conversion
Device driver conflicts	Unsupported virtual hardware (VMXNET3, SCSI)	Replace with synthetic NICs or inject proper Hyper-V drivers in advance
Missing network connectivity	NIC not mapped to Hyper-V network or disabled	Map virtual NICs correctly during conversion wizard

 

4. SCVMM Job Failures or Timeouts

Problem	Cause	Fix
Job gets stuck in "Transferring"	Library server I/O bottleneck or large disk size	Use fast local SSD/NVMe on library server; avoid network-based VMDK
"Unsupported Guest OS" error	Guest OS not recognized or too old	Convert manually or upgrade OS before conversion
Network timeout or access denied	Firewall, credentials, or DNS resolution issue	Verify Run As accounts, ports (443/5985/445), and name resolution between SCVMM and vCenter/ESXi

 

5. Post-Conversion Guest OS Issues

Problem	Cause	Fix
Activation issues (Windows)	Hardware fingerprint change triggers reactivation	Use KMS or volume licensing where possible
Services don’t start properly	Dependency on VMware-specific hardware (VMCI, virtual CD, etc.)	Clean startup items and disable VMware-related services
Time skew or sync problems	Hyper-V time integration not active	Enable Hyper-V time sync service in VM settings

 

Best Practices to Avoid These Issues

Best Practice	Benefit
Cold-shutdown VMs before conversion	Reduces corruption risk
Clean up OS (temp files, drivers)	Minimizes conversion time and issues
Verify firmware type (UEFI/BIOS)	Ensures boot compatibility
Use updated integration services	Improves Hyper-V compatibility
Test conversion in lab first	Identify app or driver-level failures in advance
Monitor SCVMM logs (Jobs tab or Event Viewer)	Provides insight into failed stages

 

Tools for Troubleshooting

·         RVTools – inventory thin vs. thick disks, OS, snapshots

·         Event Viewer on SCVMM server – look for job failure codes

·         Hyper-V VM boot logs – help debug guest-level issues

·         Sysinternals tools – check services and drivers inside guest

·         StarWind V2V Converter – fallback option for problematic conversions

 

 

Additional Prep Details from VMWare to Hyper-V

 

Key Differences That Affect Conversion Time

Provisioning Type	Description	Impact on Conversion
Thin-provisioned VMDK	Allocates space as data is written	Faster conversion — only actual data blocks are copied
Thick-provisioned VMDK	Allocates full disk size upfront	Slower conversion — full disk size is read, even unused blocks

 

 Why Thick Disks Take Longer to Convert

·         Thick disks are fully allocated (e.g., a 100 GB thick disk is actually 100 GB on disk, even if only 10 GB is used).

·         During conversion, tools like Microsoft Virtual Machine Converter (MVMC), Disk2VHD, or SCVMM's built-in V2V processes must read and copy the entire 100 GB, not just the used space.

·         Thin disks only copy the used portion of the disk, so a thin VMDK that uses 10 GB of actual data will only transfer 10 GB.

 

Conversion Tools & Behavior

Microsoft SCVMM

·         Automatically converts VMDK to VHDX during migration.

·         Attempts to detect actual data used, but performance depends on the source disk layout and whether the thick disk has zeroed blocks or not.

Third-party Tools (e.g., StarWind V2V, Disk2VHD, etc.)

·         Behavior varies—some attempt to optimize by ignoring zeroed space, others copy all sectors.

 

 

Optimization Tips before Conversion

1.      Defragment and zero out free space on thick disks using tools like sdelete from Sysinternals.

o    This allows converters to detect unused space more easily.

2.      Convert thick to thin on the VMware side before migration (if your policy allows).

3.      Shrink partitions within the guest OS to reduce copied size.

4.      Perform cold migration when possible for consistency and speed.

Estimated Migration Time Ranges

VM Disk Size	Thin Disk (used data only)	Thick Disk (full copy)
50 GB	~10–30 minutes	~30–60 minutes
100 GB	~30–60 minutes	~60–120 minutes
500 GB	~1.5–3 hours	~3–6 hours
1 TB	~3–5 hours	~6–10+ hours

Note: Assumes 1 Gbps network, moderate disk I/O, and no heavy workloads during migration.

 

What Affects Migration Speed?

Factor	Impact on Time
Disk Provisioning (Thin vs Thick)	Thin is faster—only real data is copied
Disk Usage	Less data = faster
Storage IOPS	Slow reads or writes increase time
Network Bandwidth	1 Gbps vs. 10 Gbps makes a big difference
Live vs Cold Migration	Cold is often faster and safer
Conversion Tool	Some tools optimize block copying better
Compression or Deduplication	Can help reduce copy size
Source and Destination Format	VMDK → VHDX adds conversion overhead

 

Tool-Specific Speeds (Generalized)

Tool	Notes
Microsoft SCVMM (V2V)	Efficient, but requires careful config; uses SMB/NFS/HTTP
MVMC (Legacy)	Older, slower, and no longer supported
StarWind V2V Converter	Fast and lightweight; good for one-offs
Disk2VHD + Manual import	Lightweight, but needs manual cleanup
Cloud-based tools (e.g., Azure Migrate)	Adds more time for staging and cloud prep

 

 

Where to Find Thin vs. Thick Provisioning in RVTools

·         Open RVTools and go to the vDisk tab.

·         Look for the column named:

o    thinProvisioned

§  Value: true = thin provisioned

§  Value: false = thick provisioned

 

SCVMM Concurrent Conversions Overview

The number of concurrent V2V (VMware to Hyper-V) conversions you can run in System Center Virtual Machine Manager (SCVMM) is not hard-coded, but it's limited by system resources and SCVMM configuration.

Here's a breakdown of how many you can expect and how to scale it:

 

 Typical Concurrent Conversion Capacity

SCVMM Resource Tier	Recommended Max Concurrent Conversions
Default SCVMM setup (single library server, average resources)	2–4
Well-resourced SCVMM + dedicated library server	5–10
Optimized setup with tuning and monitoring	10–15 (with caution)

Running more than 5–6 at a time on default setups can slow down conversions or cause failures, especially if disk or network bandwidth is limited.

 

What Limits Concurrent Conversions

Limiting Factor	Impact
Library Server bandwidth and IOPS	All conversions route through it
Conversion method (online/cold)	Live conversions are slower and more resource intensive
Host CPU & RAM	Conversion agents use these heavily
Network throughput	VMware > SCVMM > Hyper-V host data path
Storage target performance	Bottleneck if multiple VMs are written at once
SCVMM job scheduler	Limits job concurrency to avoid overload

 

How to Increase Concurrent Conversion Capacity

1.      Use a fast, dedicated Library Server

o    SSD storage and 10 Gbps NICs recommended.

2.      Stagger migrations

o    Use PowerShell or orchestration to batch conversions (e.g., 3 at a time).

3.      Monitor SCVMM job throughput

o    Avoid scheduling other heavy SCVMM jobs simultaneously.

4.      Use a distributed SCVMM architecture

o    Deploy additional hosts and scale out with performance tiers.

5.      Move source and target storage closer together

o    Avoid cross-site or low-bandwidth conversions.

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PowerShell for Controlled Parallel Conversions

You can use PowerShell to limit parallel conversions by queueing jobs:

## powershell $VMsToConvert = Get-SCVMWareVM | Where-Object { $_.Name -like "AppServer*" } $MaxConcurrent = 3 $Queue = New-Object System.Collections.Queue $VMsToConvert | ForEach-Object { $Queue.Enqueue($_) }             while ($Queue.Count -gt 0) {     $jobs = @()     for ($i = 0; $i -lt $MaxConcurrent -and $Queue.Count -gt 0; $i++) {         $vm = $Queue.Dequeue()         $jobs += ConvertTo-SCVirtualMachine -VMwareVM $vm -JobGroup (New-Guid) -RunAsynchronously     }     $jobs | Wait-Job }

 

 

 

 

 

 

 

 

 

 

References

 

Convert a VMware VM to Hyper-V in the VMM fabric | Microsoft Learn

Convert VMware VMs to Hyper-V faster with SCVMM | Microsoft Community Hub

V2V Converter / P2V Converter - Converting VM Formats

RVTools | Installer | 4.7.1 Installer | Dell US