> > > Is it using 64 KB writes and have you tried 256 KB writes? > > > > I use a modified 'qemu-img convert' at 64KB block size (I need 64KB for > backup). > > Maybe you'd better use a different output format that doesn't restrict you to > 64k writes.
The output format is not really the restriction. The problem is that an additional IPC layer add overhead, an d I do not want that (because it is totally unnecessary).
