Re: [Qemu-devel] [PATCH v2 1/1] Add QMP bits for blockdev-snapshot-sync.

[Jes Sorensen]

On 04/27/11 17:05, Luiz Capitulino wrote:
>> +If a new image file is specified, the new image file will become the
>> > +new root image. If format is specified, the snapshot file will be
>> > +created in that format. Otherwise the snapshot will be internal!
>> > +(currently unsupported).
> Sorry for the stupid question, but what's a "new root image"? Also, all
> these assumptions seem human features to me, as it can save some typing
> and I can poke around to see where the snapshots are stored.
> 
> All arguments should be mandatory in QMP, IMO.

Sorry, but there is absolutely no reason to make all arguments
mandatory. Sure it can be done, but the only result is a separate
handling function for it, so we got more almost identical, but still
different code to maintain.

> Finally, what's the expect behavior when -snapshot is used? I'm getting
> this:
> 
>  (qemu) snapshot_blkdev ide0-hd0 snap-test
>  Could not open '/tmp/vl.6w8YXA'
>  (qemu)

What type of file system is your /tmp? You need to provide full path to
the snapshot file if you don't want it created next to where your qemu
binary is being executed.

> At first, I don't see why we shouldn't generate the live snapshot, but anyway,
> any special behavior like this should be noted in the section called Notes
> in the command's documentation.
> 

I don't follow this at all, please elaborate.

Jes