[sheepdog-users] About New Futures

[Liu Yuan]

On Fri, Aug 09, 2013 at 05:30:35PM +0200, Valerio Pachera wrote:
> 2013/8/9 MORITA Kazutaka <morita.kazutaka at gmail.com>:
> > I pushed the patch to the master.  It's available now.
> 
> I notice now that the patch has been written only 6 hours ago! ;-)
> 
> > Maybe, you misunderstood something I wrote.  Basically, it's difficult
> > for block device storage to know that which blocks are not used by
> > guest file system.
> 
> I found the discussion, but it was with Yuan.
> The object was 'vdi and dynamic allocation'
> 
> 2012/12/14 Liu Yuan <namei.unix at gmail.com>:
> > This is similar to linux file punch holes to safe disk space.
> > Okay, "optimize" is indeed a better wording. let's firstly implement a
> > mechanism to optimize the underlying storage allocation via 'collie vdi
> > optimize'. This feature is in the plan.
> 
> I don't consider this an important future but I was curious to know if
> was already present.

Well, with discard/trim support, all-zero objects will be automatically removed
from cluster. So this 'optimize' command will duplicate the function and not
necessary.

There is still another way to discard all-zero objects for now with qemu-img if
you don't enable discard support within guest yet.

1 qemu-img convert sheepdog:image local_image # this will auto-trim zeroes for local_image
2 qemu-img convert local_image sheepdog:image # Now zero objects are all trimmed

Thanks
Yuan