[libvirt] virStorageVolCreateXMLFrom

[Kenneth Nagin]

>"Daniel P. Berrange" <berrange at redhat.com> wrote on 22/06/2009 12:08:39:

> On Mon, Jun 22, 2009 at 09:59:00AM +0300, Kenneth Nagin wrote:
> >
> > I'd like to get a better understanding of the
virStorageVolCreateXMLFrom
> > api Its name and signature imply that it is a cloning operation that
copies
> > a volume from one location to another. Is this correct?
>
> Yes this method does a deep-copy of all the data, and can convert between
> disk formats at the same time (eg raw -> qcow2, or any qemu-img format).
>
> > Does it support remote copy of non-shared storage, e.g. from a http
server?
>
> It only supports copying within the same storage pool at this time, and
> we don't implement any storage pool based on http.
>
> > Is there any thought about adding digest validation check, e.g. with a
md5
> > digest?
>
> What would that do ? Or rather what semantics would you want from such a
> thing ?  I rather hope that just reading & writing a local file would
> not result in data corruption.
My question was in the context of supporting remote copy (see above).
The digest validation would only be necessary if you supported remote copy.

>
> > Is copy-on-write cloning supported in this command?
>
> No, you can create copy on write volumes using the <backingStore> element
> in the XML description
>
> http://libvirt.org/formatstorage.html#StorageVolBacking
>
> This is supported for LVM volumes, qcow, qcow2 and vmdk files at this
time.
>
> Regards,
> Daniel
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