Re: [Qemu-devel] [RFC] introduce bitmap to bdrv_commit totrackdirtysector

[Zhang Haoyu]

On 2015-03-10 10:58:44, Fam Zheng wrote:
> > Is it worthy to implement it?
> 
> Maybe, I think once we start to assign node-name to each BDS in the tree, this
> will be natural to implement.
> 
Once implemented, to be honest, I really don't see much advantages of 
incremental backup over aforementioned mechanism(external snapshot + active 
block commit),
especially, regarding the case of source vm non-normal shutdown, full copy is 
needed,
and corresponding check mechanism is needed too.
I think so much exceptional scenarios are needed to be considered for 
incremental backup mechanism.
Maybe I missed something.

Thanks,
Zhang Haoyu
> > And does qemu support commit any external snapshot to its backing file?
> 
> Yes.