Run a defragmentation and zero-fill utility inside Windows 8 (like SDelete: sdelete -z C: ). Shut down the virtual machine. Convert and compress the file using qemu-img :
Virtualization administrators and enthusiasts frequently use QCOW2 (QEMU Copy-On-Write) disk images due to their storage efficiency and advanced feature set. When deploying legacy operating systems like Windows 8 or Windows 8.1 within Proxmox VE, KVM, or QEMU, leveraging the QCOW2 format is the industry standard. windows 8 qcow2
qemu-system-x86_64 -m 4096 -smp 2 -cpu host \ -drive file=win8.qcow2,format=qcow2 \ -cdrom windows8.iso -boot d Run a defragmentation and zero-fill utility inside Windows