Re: [Qemu-devel] [Nbd] [PATCH v2] doc: Add NBD_CMD_BLOCK_STATUS extension

[Paolo Bonzini]

On 05/04/2016 17:27, Alex Bligh wrote:
>>> I'm missing how the ugh-author can write the software without knowing
>>> exactly what the bit does. Or are you saying "that's a matter
>>> for the qemu spec, not the nbd spec"?
> > 
> > Yes, that's it.  NBD defines a safe default and a general idea of what
> > it should be used for.
>
> OK, so my argument then is we should not have a special case
> 'only Qemu knows what this does' bit if we can avoid at, and
> instead have a general system of 'proprietary bits' (unfortunate
> word but perhaps 'non-NBD').

I think it is generic enough.  Ideally the backup software wouldn't see
the QEMU-specific bits, those would be provided by a management layer
(such as OpenStack/Virtuozzo/oVirt/ProxMox).  They would just know to
copy the dirty bits.

Paolo