Windows 10qcow2 ●

Virtualization Engineering Team Appendices available upon request: Sample libvirt domain XML for Windows 10 QCOW2, PowerShell optimization script.

If you are running a Linux host (like Ubuntu, Fedora, or Arch) and need Windows 10 for specific apps or testing, KVM + QCOW2 delivers near-bare-metal performance. Unlike VirtualBox, KVM is a Type-1 hypervisor, and QCOW2 is optimized for this environment.

A 100GB virtual disk only occupies the space of the actual files inside it (e.g., 25GB for a fresh Windows 10 install).

qemu-img create -f qcow2 -o preallocation=metadata windows10.qcow2 60G windows 10qcow2

If you have an existing Windows 10 virtual machine running in VMware ( .vmdk ), VirtualBox ( .vdi ), or raw format ( .img ), you can convert it to QCOW2 using the qemu-img tool. Convert VMDK (VMware) to QCOW2

Incorrect CPU configuration or missing storage drivers during a migration.

# Add 20GB to the existing disk image qemu-img resize windows10.qcow2 +20G Use code with caution. A 100GB virtual disk only occupies the space

Open . You will notice several devices marked with yellow exclamation points (such as the PCI Simple Communications Controller). Right-click the missing device and select Update Driver .

Windows 10 doesn’t know it’s running on a QCOW2 image. Without tuning, performance can be sluggish.

Deploying Windows 10 as a QCOW2 image provides distinct advantages for sysadmins and developers: # Add 20GB to the existing disk image

In the VM storage hardware settings, set the option to unmap .

Inside Windows 10, optimize and trim the drive, or run a zero-fill tool like Sysinternals SDelete ( sdelete64.exe -z c: ). Shut down the virtual machine completely. Run the host-side compression command:

Enable the discard mount option to allow the guest OS to tell the QCOW2 file to shrink when files are deleted inside Windows. Converting ISO or VMDK to QCOW2