Re: -drive if=none: can't we make this the default?

[Peter Maydell]

On Thu, 2 Nov 2023 at 10:43, Kevin Wolf <kwolf@redhat.com> wrote:
>
> Am 01.11.2023 um 12:21 hat Peter Maydell geschrieben:
> > On Tue, 31 Oct 2023 at 18:45, Kevin Wolf <kwolf@redhat.com> wrote:
> > > Am 16.10.2023 um 13:58 hat Michael Tokarev geschrieben:
> > > > Almost everyone mentions -blockdev as a replacement for -drive.
> > >
> > > More specifically for -drive if=none. I honestly don't know many common
> > > use cases for that one.
> >
> > One use case for it is "create a drive with a qcow2 backend to use
> > for -snapshot snapshots, but don't plug it into anything". See
> > https://translatedcode.wordpress.com/2015/07/06/tricks-for-debugging-qemu-savevm-snapshots/
> > I dunno whether that counts as "common", though :-)
>
> Ok, I was already wondering what good -snapshot was for an image that
> isn't even used, but what the article describes is actually not using
> -snapshot, but internal snapshots with savevm/loadvm, i.e. using the
> image to store the VM state.
>
> This actually makes a lot of sense for if=none, as one of the few cases
> where "none" accurately tells what device it will be used with.

Whoops, have I got the terminology wrong again? To me these are
"snapshots" (they do store the whole VM state including the current
state of the disk, and "qemu-img info" lists them as "snapshots"),
whereas I never use the '-snapshot' option, so I never remember
that we have two different things here. Sorry for introducing
confusion :-(

thanks
-- PMM