Am 19.06.2013 um 16:02 hat Philipp Hahn geschrieben: > Hello, > > while working on a Xen-VM I noticed that qemu-img does not support the > backing file mechanism of vpc/vhd files, but Xens blktap2 does; it has a > libvhd and some tools to create and modify vpc/vhd files: > [...] > > Is the lack of support for backing files in vpc/vjd in qemu just a question > of time / interest, are there technical problems, or are there some political > issues?
Nobody wrote the code, that's all. Read-only support should be almost trivial, and for read-write we'd have to add some real code to deal with the block bitmaps (without backing files we get away with what is mostly a slow fake implementation). Kevin
