Ensure OVMF is installed (e.g., sudo apt install ovmf on Debian/Ubuntu). You typically need to point QEMU to the OVMF_CODE.fd and OVMF_VARS.fd files.

From a VMDK (VMware):

Note the bus=sata parameter—this avoids the need to load VirtIO drivers during installation, allowing the installer to detect the disk immediately. You can convert to VirtIO later by installing the drivers and changing the bus type.

Each QCOW2 image has a header, L1 table, L2 tables, and data clusters. When a VM performs I/O, the hypervisor needs to reference these tables—without proper caching, this requires per disk access, which is expensive.

These optimizations significantly reduce CPU overhead in the VM.

Windows 81 Qcow2 Install Jun 2026

Ensure OVMF is installed (e.g., sudo apt install ovmf on Debian/Ubuntu). You typically need to point QEMU to the OVMF_CODE.fd and OVMF_VARS.fd files.

From a VMDK (VMware):

These optimizations significantly reduce CPU overhead in the VM. Ensure OVMF is installed (e.g.