On Fri, Aug 27, 2021 at 02:40:30AM -0700, Joseph Lee wrote: nbdfuse, part of the libnbd project, can do this (with writes). In fact there is an example of doing exactly this in the manual: https://libguestfs.org/nbdfuse.1.html#Use-qemu-nbd-to-read-and-modify-a-q... https://gitlab.com/nbdkit/libnbd By the way I would be extremely wary of any tool which claims to process qcow2 files but is not using qemu code to do it. nbdfuse uses qemu-nbd (ie qemu code). Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top