Re: [Libguestfs] Inspection of disk snapshots

> This makes a copy of the whole disk image. It's also not a consistent > (point in time) copy. Oh I see that you're copying the _snapshot_ that you created with libvirt; it's not a whole disk copy. There's still not any point in doing this, and what I said below stands. > > At that point I mount it through libguestfs and inspect its content. > > As long as you use the 'readonly=1' flag (which is really *essential*, > else you'll get disk corruption), you can just point libguestfs at the > base image: > > g = guestfs.GuestFS (python_return_dict=True) > g.add_drive_opts ("base_image.qcow2", format="qcow2", readonly=1) > > That also doesn't get you a consistent snapshot, but it'll work most > of the time, and give you a clear error in libguestfs when it doesn't > (and won't corrupt your base disk or anything like that, provided > you're using readonly=1). > > The effect of the readonly=1 flag is to create an external snapshot. > It is roughly the equivalent of doing: > > qemu-img create -f qcow2 -b base_image snapshot.qcow2 > < point libguestfs at snapshot.qcow2 > > > If you want lightweight, consistent, point-in-time snapshots (which it > sounds like you do), qemu has recently been adding this capability. > See the 'drive-backup' monitor command. I've not tried using that

> and I don't know if it is wired up through libvirt,

> but libguestfs should be able to consume it since it's just an NBD > source.