Search
StarWind is a hyperconverged (HCI) vendor with focus on Enterprise ROBO, SMB & Edge

Migrating and Configuring Hyper-V Passthrough Disks

  • October 3, 2024
  • 12 min read
StarWind Solutions Architect. Anton excels in storage, virtualization, and networking, specializing in architecting highly efficient infrastructures for clients.
StarWind Solutions Architect. Anton excels in storage, virtualization, and networking, specializing in architecting highly efficient infrastructures for clients.

Without a clear understanding of how to migrate and configure Hyper-V passthrough disks, system administrators can face significant downtime, data loss, and frustration. These issues can hinder productivity and escalate operational costs, impacting overall business efficiency.

This article will guide you through the process of migrating and configuring Hyper-V passthrough disks, providing step-by-step instructions to ensure a smooth transition. By following these guidelines, you can optimize your virtualized storage environment, enhance performance, and maintain data integrity.

What Is Hyper-V Storage Migration?

Hyper-V Storage Migration is the process of moving virtual machine (VM) storage from one location to another without significant downtime or disruption to the running VMs. This enhanced feature was introduced in Windows Server 2012 and has changed the way we approach server virtualization, workload management, resource utilization, and storage virtualization. It allows administrators to maintain VM availability while reallocating storage resources, optimizing performance, and managing storage capacity more effectively. By utilizing Hyper-V Storage Migration, organizations can ensure seamless operations and efficient storage management in a dynamic virtualized environment.

To gain a comprehensive understanding of Hyper-V Storage Migration technology, let’s explore its key features:

  • Hyper-V Storage Migration supports the transfer of both VHD and VHDX files.
  • Virtual hard disks used by a VM can be migrated to a different storage device while the virtual machine is still running.
  • Data can be transferred between virtual machines within a single Hyper-V host or across different Hyper-V hosts.
  • This migration process can be managed through Hyper-V Manager, Windows Failover Cluster, PowerShell, or System Center Virtual Machine Manager.
  • The process involves moving the storage, not the VM itself, to a new location.
  • The destination storage can be either local or remote, but the Hyper-V host must have access to it.
  • You can configure the number of concurrent storage migrations on a host. By default, two migrations can run simultaneously. To adjust this setting, open Hyper-V Manager, go to Hyper-V Settings in the Actions section, select Storage Migrations, and enter the desired value.

Passthrough Disk Advantages and Disadvantages

Advantages

  • High Performance: Passthrough disks offer near-native performance by providing direct access to the physical disk, making them ideal for I/O-intensive applications.
  • Storage Flexibility: These disks allow the use of large amounts of storage, accommodating larger data sets without the limitations of virtual hard disk (VHD) files.
  • Backup Efficiency: By utilizing passthrough disks, backup operations can be more efficient as data is accessed directly, reducing overhead.

Disadvantages

Live Migration Limitations: Passthrough disks do not support Hyper-V live migration, which can restrict flexibility in managing VMs across different hosts.

Backup Challenges: While passthrough disks can enhance backup efficiency, they can also complicate backup and restore processes due to their direct access nature and lack of integration with standard Hyper-V backup solutions.

How Hyper-V Passthrough Disks Migration Works

Hyper-V Passthrough Disks Migration involves moving a virtual machine’s passthrough disk to a different storage location while minimizing downtime and maintaining the VM’s operational status. Here’s a step-by-step overview of how it works:

Initiation: The migration process is initiated using tools like Hyper-V Manager, Windows PowerShell, or System Center Virtual Machine Manager (SCVMM). This can be done while the VM is online, allowing continuous operation during the transfer.

Data Transfer: The migration process begins with transferring the passthrough disk data to the target storage. The data is copied directly from the source disk to the destination, ensuring data integrity and consistency.

Switch Over: Once the data transfer is complete, the VM’s configuration is updated to point to the new storage location of the passthrough disk. This update is typically seamless, with minimal impact on the VM’s performance.

Completion: After the switchover, the VM continues to run from the new passthrough disk location. Final checks are performed to ensure that the migration was successful and that the VM operates correctly with the new storage configuration.

How to Configure a Passthrough Disk in Hyper-V

Configuring a passthrough disk in Hyper-V involves several steps to ensure proper setup and functionality. Below is a step-by-step guide to help you configure a passthrough disk. Note that while I can’t provide actual screenshots, I’ll describe where to expect visual cues and what to look for in the Hyper-V Manager.

Step 1: Prepare the Physical Disk

Initialize the Disk:

  • Open Disk Management by right-clicking on the Start button and selecting Disk Management.
  • Locate the disk you want to use as a passthrough disk.
  • If the disk is new, right-click on it and select Initialize Disk. Choose either MBR (Master Boot Record) or GPT (GUID Partition Table) as the partition style.

Bring the Disk Offline:

  • In Disk Management, right-click the disk again and select Offline. The disk must be offline for Hyper-V to use it as a passthrough disk.

Step 2: Add the Passthrough Disk to a Virtual Machine

  • Launch Hyper-V Manager from the Start menu or Administrative Tools.

Select the Virtual Machine:

  • In the left pane, select the Hyper-V host where your virtual machine resides.
  • In the middle pane, right-click on the VM to which you want to add the passthrough disk and select Settings.

Add a SCSI Controller:

  • In the VM settings window, click Add Hardware.
  • Select SCSI Controller and click Add.

Add a Hard Drive:

  • Under the SCSI Controller you just added, select Hard Drive and click Add.

Under the SCSI Controller you just added, select Hard Drive and click Add

 

  • In the right pane, select Physical hard disk.
  • From the drop-down menu, select the offline physical disk you prepared earlier.
  • Click Apply and then OK to save the changes.
    Click Apply and then OK to save the changes

 

Step 3: Bring the Disk Online in the Virtual Machine

  • Start the Virtual Machine:
  • In Hyper-V Manager, right-click on the VM and select Start.

Open Disk Management in the VM:

  • Connect to the VM and open Disk Management within the guest operating system.

Initialize and Format the Disk:

  • If the disk is not initialized, follow the initialization steps as you did on the host machine.
  • Format the disk as needed within the guest operating system.

Step 4: Verify the Passthrough Disk Configuration

  • Check Disk Availability:
  • Ensure the passthrough disk is available and correctly mapped within the VM by checking This PC or Disk Management in the guest OS.
  • Perform read and write operations to confirm that the passthrough disk is functioning correctly.

Conclusion

Migrating and configuring Hyper-V passthrough disks can significantly enhance the performance and flexibility of your virtualized environment. Understanding the advantages and disadvantages of passthrough disks, as well as the steps involved in their configuration and conversion, is crucial for efficient storage management. By following the detailed instructions provided, you can ensure a seamless transition from physical to virtual storage, optimize your VM operations, and maintain data integrity. Proper management of passthrough disks enables you to leverage the full potential of Hyper-V, ensuring your virtual infrastructure remains robust and adaptable to evolving needs.

Hey! Found Anton’s article helpful? Looking to deploy a new, easy-to-manage, and cost-effective hyperconverged infrastructure?
Alex Bykovskyi
Alex Bykovskyi StarWind Virtual HCI Appliance Product Manager
Well, we can help you with this one! Building a new hyperconverged environment is a breeze with StarWind Virtual HCI Appliance (VHCA). It’s a complete hyperconverged infrastructure solution that combines hypervisor (vSphere, Hyper-V, Proxmox, or our custom version of KVM), software-defined storage (StarWind VSAN), and streamlined management tools. Interested in diving deeper into VHCA’s capabilities and features? Book your StarWind Virtual HCI Appliance demo today!