Re: [Qemu-devel] Adding Save States menu items

[Peter Maydell <peter.maydell@linaro.org>]

On 6 October 2016 at 12:59, Eric Blake <eblake@redhat.com> wrote:
> Libvirt also learned that the qemu 'migrate-to-disk' format (used by
> 'savevm' or 'migrate') is NOT self-descriptive - in order to fully and
> safely revert to an earlier state, you HAVE to store the command line
> (or a way to regenerate the command line) that was associated with the
> qemu whose state you saved, along with tracking all hotplugs.  Since a
> mere 'savevm' REQUIRES external information to safely be restored, you
> would have to figure out a way to store this additional information
> alongside whatever save files you plan on creating (and please don't
> change the qcow2 file format to become a dumping grounds for this
> additional information).

Good point. I think this is a fairly strong argument for
keeping the "user friendly" interface to snapshots in the
VM management layer, not QEMU itself.

thanks
-- PMM