Re: [Qemu-devel] [PATCH v4 0/6] Efficient VM backup for qemu

[Dietmar Maurer]

> > If we use nbd, how can we pass additional information to the other
> > side, for example information about unallocated regions?
> >
> 
> You can either send trim commands, or just skip those regions and let the 
> other
> side figure it out.

But we are lost if we want to transfer something else? I am currently not sure 
what we
want to transfer, but I am sure we will find something in future.

Or can we simply add a header to each write with additional information?