Re: [Qemu-devel] [PATCH v3 resend 7/8] rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition

[Michael R. Hines]

On 10/08/2013 12:05 PM, Paolo Bonzini wrote:
> Il 08/10/2013 16:49, Eric Blake ha scritto:
> > You are now returning a state that older libvirt versions are not
> > expecting.  Obviously, we can patch newer libvirt to make migration work
> > again, but should we be thinking about damage control by stating that an
> > older management app should still be able to drive migration on a new
> > qemu?  Or is it acceptable to state that newer qemu requires newer
> > management tools?
> We strive for that, but sometimes we break because we do not really know
> what management expects from QEMU.
>
> In this case, in particular, I think a capability is a bit overkill.
> Libvirt needs to be somewhat liberal in what it accepts; in this case it
> can treat any unknown state as "active".
>
> Paolo

That makes sense to me too - the setup state is "effectively" the same
as active and can be safely treated as such.

There's a similar issue MigrationInfo statistics - what's the
backwards/forwards-compatible procedure for not breaking libvirt
when new statics appear? - such as "setup-time", which timestamps
the new state that was introduced?

- Michael
for adding new statistics

- Michael