Re: [Qemu-devel] [PATCH 3/3] Add nocreate option to snapshot_blkdev

[Paolo Bonzini]

On 02/23/2012 11:19 AM, Federico Simoncelli wrote:
>>> I'm worried that blkmirror does not satisfy _all_ mirroring
>>> needs, for example you cannot use block_stream to copy from the
>>> source to the destination, so perhaps in the future we want to
>>> change it to something else.
> 
> Are you talking about a mirroring where you block_stream the missing 
> clusters in the destination from the source? I believe that it could
> be done without losing the blkmirror modularity probably extending
> the BlockDriver structure with some additional concepts.

Yes, agreed.  It's not the idea of a driver that I don't like; it is
making it available through the command-line that worries me.  This
would be unlike all other "filtering" options (copy-on-read, I/O limits,
dirty sector tracking).  True, there are blkdebug and blkverify but
those are for debugging only.

Paolo