Inside Windows: Run Defragment and Optimize Drives -> Optimize (This allows the guest to mark free space).
Virtualization has changed the way developers, IT professionals, and power users interact with operating systems. While VirtualBox and VMware are popular choices, the open-source powerhouse QEMU (Quick Emulator) combined with KVM (Kernel-based Virtual Machine) offers near-native performance on Linux systems. At the heart of this setup lies a specific file type: Windows 10.qcow2 .
<driver name="qemu" type="qcow2" cache="none" io="native"/> Over time, your Windows 10.qcow2 file grows. Even if you delete files inside Windows, the image file on your Linux host stays large. To reclaim space:
-drive file=Windows 10.qcow2,format=qcow2,if=virtio,aio=native,cache.direct=on For libvirt (virt-manager), edit the VM XML: