qemu-img create -f qcow2 -o preallocation=metadata win81.qcow2 40G
Minimum 20 GB of free space on the host drive. Windows 8.1 ISO: A valid installation media image.
virsh domblklist win81 # Find disk target (e.g., vda) virsh snapshot-create --disk-only --atomic win81 cp /var/lib/libvirt/images/windows81.qcow2 /backup/windows81_backup.qcow2 virsh blockcommit win81 vda --active --verbose --pivot windows 81 qcow2 install
Virtualization allows you to run legacy operating systems smoothly on modern hardware without dual-booting. Windows 8.1 remains a popular choice for virtualization because it is lightweight, highly stable, and less resource-intensive than Windows 10 or 11.
If the VM hangs during restarts, ensure your QEMU CPU type is set to host or kvm64 . Windows 8.1 requires specific CPU features like CMPXCHG16b, PrefetchW, and LAHF/SAHF to boot properly. qemu-img create -f qcow2 -o preallocation=metadata win81
Method B: Graphical Interface (Virtual Machine Manager / virt-manager ) Open and choose Create a New Virtual Machine .
qemu-system-x86_64 -M q35,usb=on,acpi=on,hpet=off -m 4G -smp cores=4 -accel kvm -cpu host -drive file=win81.qcow2 -cdrom /path/to/your/windows8.1.iso -device VGA,vgamem_mb=256 -nic user,model=e1000 -usb -device usb-tablet Windows 8
The disk cache setting significantly impacts performance. For Windows 8.1, the recommended cache mode is (or "none" in some configurations):
Once the driver is loaded, your virtual disk will appear. Select it and click Next to begin copying files.
To ensure maximum performance, boot the virtual machine using hardware acceleration ( -enable-kvm ) and attach both the Windows 8.1 installer and the VirtIO driver disc. Execute this command to start the installation environment: