Re: [Qemu-devel] Some question about savem/qcow2 incremental snapshot

[Stefan Hajnoczi]

On Tue, Jan 9, 2018 at 7:55 PM, Dr. David Alan Gilbert
<address@hidden> wrote:
>> Certain guest operations like rebooting or zeroing memory will defeat
>> the incremental guest RAM snapshot feature.  It's worth thinking about
>> these cases to make sure this feature would be worth it in real use
>> cases.
>
> But those probably wouldn't upset an NVDimm?

If the guest dirties all RAM then the incremental snapshot feature
degrades to a full snapshot.  I'm asking if there are common
operations where that happens.

I seem to remember Windows guests zero all pages on cold boot.  Maybe
that's not the case anymore.

Worth checking before embarking on this feature because it could be a
waste of effort if it turns out real-world guests dirty all memory in
common cases.