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

[He, Junyan]

hi all:

I am now focusing on snapshot optimization for Intel NVDimm kind memory. 
Different from the normal memory, the NVDimm may be 128G, 256G or even more for 
just one guest, and its speed is slower than the normal memory. So sometimes it 
may take several minutes to complete just one snapshot saving. Even with 
compression enabled, the snapshot point may consume more than 30G disk space. 
We decide to add incremental kind snapshot saving to resolve this. Just store 
difference between snapshot points to save time and disk space.
But the current snapshot/save_vm framework seems not to support this.
We need to add snapshot dependency and extra operations when we LOAD and DELETE 
the snapshot point.
Is that possible to modify the savevm framework and add some incremental 
snapshot support to QCOW2 format?

Thanks