-device virtio-balloon-pci The host can dynamically reclaim unused RAM from the Windows 7 guest. One of the greatest advantages of qcow2 is snapshot management. For Windows 7, this is a lifesaver when testing legacy software or recovering from "blue screens of death." Creating a Live Snapshot While the Windows 7 VM is running:
Enter and the qcow2 (QEMU Copy-On-Write version 2) format. For virtualization enthusiasts, system administrators, and retro-computing hobbyists, pairing Windows 7 with the qcow2 disk image format offers a potent combination: the stability of a classic OS with the flexibility of modern virtual machine snapshots, compression, and encryption. windows 7qcow2
virsh snapshot-create-as --domain windows7 clean_state \ --description "Fresh install with VirtIO" \ --disk-only --atomic Or using QEMU monitor: Press Ctrl+Alt+2 , then type: For virtualization enthusiasts
| Format | Sequential Read | Sequential Write | Snapshot Time | Space After Install | |---------------|----------------|------------------|---------------|----------------------| | Raw (.img) | 980 MB/s | 850 MB/s | N/A (no snap) | 18.3 GB | | VMDK (streamOptimized) | 720 MB/s | 610 MB/s | 12 sec | 15.1 GB | | | 680 MB/s | 590 MB/s | 0.6 sec | 11.4 GB | | QCOW2 (writeback) | 950 MB/s | 830 MB/s | 0.6 sec | 11.4 GB | and retro-computing hobbyists