Re: [Qemu-block] Closing Bitmaps (Was: Re: [Qemu-devel] [PATCH v7 03/24] block: Release dirty bitmaps in bdrv_close())

[John Snow]

On 11/18/2015 10:03 AM, Kevin Wolf wrote:
> Am 17.11.2015 um 18:05 hat John Snow geschrieben:
>> Still the subject of debate on-list, but the thought is roughly this:
>>
>> Bitmaps will be able to flush-to-file on close. (If they have no
>> persistence data, it's a no-op (maybe.)) This might mean being flushed
>> to their own BDS -- the one they are describing -- as a qcow2 extension.
>> Or, it could be to an arbitrary new standalone file format designed for
>> the sole purpose of containing bitmap data.
>>
>> The discussion hasn't progressed beyond "Max and Kevin do not think
>> storing arbitrary bitmaps in .qcow2 files is a good idea." The logical
>> conclusion is "We need a new standalone format, then" but we haven't
>> decided what that format will look like or how it will be used.
> 
> I think the actual logical conclusion is that you use qcow2 images in
> order to use the feature.
> 
> Kevin
> 

It's fine to say "To hell with raw," but for networked filesystems and
other configurations that aren't using the qcow2 driver, I think it
won't be a sufficient answer.

qcow2 support is my first priority, but I think it can't be my only one.