On Fri, Nov 01, 2013 at 06:04:19AM +0100, Philipp Hahn wrote: > Hello, > > sorry for high-jacking this thread, but I have a questing regarding VHD > (without the X): Xen-4.3 switched to upstream QEMUs support for VHD. The > dropped their own VHD implementation in blktap2, which supported backing > chains, which QEMU currently doesn't. The Xen implementation > (xen/tools/blktap2/vhd/lib/ is BSD 3 clause) also supports some kind of > journal. > 1. Does someone know if the journal support for VHD is somehow related to > VHDX?
I don't believe it is. Despite the similarity in names, VHD and VHDX are completely different formats. I just went and looked at Xen's libvhd-journal, and per my understanding it is a journal written into a separate file, not related to the actual VHD spec itself. It appears to be used by the VHD utility tools, when updating a VHD image file with operations such as resize, etc.., so they can write a finalized bitmap of all header/metadata changes at once to minimize any potential corruption. Jeff <snipped the rest>