On Thu, Jan 12, 2017 at 3:44 PM, Alex Bligh <a...@alex.org.uk> wrote: >> On 12 Jan 2017, at 14:43, Eric Blake <ebl...@redhat.com> wrote: >> That's because the NBD protocol lacks a resize command. You'd have to >> first get that proposed as an NBD extension before qemu could support it. > > Actually the NBD protocol lacks a 'make a disk with size X' command, > let alone a resize command. The size of an NBD disk is (currently) > entirely in the hands of the server. What I think we'd really need > would be a 'reread size' command, and have the server capable of > supporting resizing. That would then work for readonly images too.
That would be fine for QEMU. Resizing LVM volumes or host block devices works exactly like this. Stefan
