Re: [Qemu-devel] [PATCH 2/2 v2] Add the blockdev-reopen and blockdev-migrate commands

[Paolo Bonzini]

On 02/27/2012 01:12 PM, Luiz Capitulino wrote:
> > If I didn't make any mistake in the code I'm just enforcing that when
> > you specify "incremental" you also need a new image.
> > There are still other valid cases where they are optional.
> 
> Which operation will be performed if 'incremental' is not passed? If
> it's passed, which operation will be performed if 'new_image_file' is not?

There are four cases:

1) incremental=false, new_image_file not passed:
   right now fail; in the future:
   - create an image on dest with no backing file;
   - writes will be mirrored to current_image_file and dest
   - start streaming from current_image_file to dest

2) incremental=false, new_image_file passed:
   right now fail; in the future:
   - create an image on dest with no backing file;
   - live-snapshot based on current_image_file to new_image_file;
   - writes will be mirrored to new_image_file and dest
   - start streaming from current_image_file to dest

3) incremental=true, new_image_file not passed:
   - error

4) incremental=true, new_image_file passed:
   - no images will be created
   - writes will be mirrored to new_image_file and dest

Paolo