Comment 9 for bug 601946

That was also my feeling, so nice to get a confirmation!

Another related thing would be to allow qemu-nbd to write compressed blocks its backing image - today if you use a qcow2 with compression, any block which is written to gets uncompressed in the resulting image and you need to recompress the image offline with qemu-img.

Would you have any pointers/documentation on how best to implement this so both qemu-img and qemu-nbd can use multithreaded compressed writes ? I'm totally new to qemu block subsystem.