On 06/10/2010 08:08 AM, Kevin Wolf wrote:
Am 10.06.2010 14:53, schrieb Anthony Liguori:
On 06/10/2010 04:43 AM, Kevin Wolf wrote:
Huh, why this? Seems I still haven't understood all of qcow2 then... I
always thought that there's just a specific offset where VM state
starts, but no explicit end.
A live snapshot can last for a very long time. What happens if you need
to allocate a new block for disk I/O while saving a snapshot?
You allocate it, I guess?
Note that VM state must be virtually contiguous, but not necessarily
physically (virtually = on the virtual hard disk as seen by the guest;
physically = in the image file). It's just not seen by the guest because
it's saved at a high offset that is after the end of the real disk
content, but otherwise it should behave the same as guest data.
I guess you could just start writing and then once your finished, you
could update the snapshot information. So yeah, I think your right that
it's doable with the current format.
Regards,
Anthony Liguori
Kevin
