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iostat -x 1 /dev/loop0 # if using loop device (not recommended) # Better: qemu-img bench qemu-img bench -c 1000 -d 64 -f qcow2 -s 64k -t writeback -o win7.qcow2 Look for low %util and high MB/s . If you see high latency, increase host RAM or move the qcow2 to an NVMe or SSD storage pool. — that ruins "top" performance. Part 6: Advanced qcow2 Operations for Windows 7 Power Users 6.1 Snapshots: The Killer Feature Snapshots let you test patches or software without risk:
: For a production Windows 7 VM, qcow2 is the smart choice. For a "top" experience, we mitigate its overhead via caching, alignment, and guest drivers. Part 2: Creating the Ideal Windows 7 qcow2 Image 2.1 Minimum and Recommended Sizing Do not create a tiny qcow2. Windows 7 with updates and a few apps needs room to breathe. windows 7 qcow2 top
defrag C: /L /U /V Then use from Sysinternals to zero free space: iostat -x 1 /dev/loop0 # if using loop
Snapshots are stored inside the qcow2 file. Over many snapshots, performance degrades. To clean up: Part 6: Advanced qcow2 Operations for Windows 7
