[Sheepdog] [PATCH 0/5] modify the usage of snapshot and cloning

[MORITA Kazutaka]

On Mon, Jan 11, 2010 at 7:03 AM, Chris Webb <chris at arachsys.com> wrote:
> MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp> writes:
>
>> What I thought is that the apply command moves the position of HEAD.
>> For example,
>>
>>   $ shepherd info -t vdi -f tree john
>>   john---[tag_1]-+-[tag_2]---HEAD
>>                  `-[tag_3]
>>
>>   $ shepherd apply john:tag_1 delta_file
>>   (New image is created and it becomes HEAD. Previous HEAD becomes a snapshot.)
>>
>>   $ shepherd info -t vdi -f tree john
>>   john---[tag_1]-+-[tag_2]---[tag_4]
>>                  +-[tag_3]
>>                  `-HEAD
>
> Actually, I'm not I completely understand why this isn't:
>
>  $ shepherd info -t vdi -f tree john
>  john---[tag_1]-+-[tag_2]---HEAD
>                 +-[tag_3]
>                 +-[tag_4]

This seems to be better than what I suggested because there is
no need to move HEAD in applying a delta.

>  $ shepherd info -t vdi -f tree john
>  john---[tag_1]-+-[tag_2]
>                 +-[tag_3]
>                 +-[tag_4]---HEAD

This discards the difference between [tag_2] and the old HEAD.

Regards,

Kazutaka Morita