Re: [Qemu-devel] from which version qemu support clone on rbd

[Stefan Hajnoczi]

On Wed, Jul 02, 2014 at 11:17:40PM +0800, yue wrote:
 i now look at qemu 2.0, i do not find rbd-api related to clone.
 if qemu support this function? and from which version?
 clone api of rbd is very simple(one api), why qemu does not implement?what is 
 the reason?

rbd_snap_create()?  QEMU supports it.

Maybe clones are a different concept from snapshots in RADOS.  I have
CCed Josh Durgin from Ceph.  Please CC in the future for questions about
rbd.

Stefan


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[Qemu-devel] from which version qemu support clone on rbd

[yue]

hi,all
 
i now look at qemu 2.0, i do not find rbd-api related to clone.
if qemu support this function? and from which version?
clone api of rbd is very simple(one api), why qemu does not implement?what is 
the reason?
 
 
 
thanks.

Re: [Qemu-devel] from which version qemu support clone on rbd

[Brian Jackson]

Qemu doesn't handle that level of abstraction. The closest approximation 
you could probably come up with is qemu-img's backing file support for 
qcow2 images.


You should stick to using the rbd tool to create clones of rbd devices. 
Alternatively, use a higher level tool (like openstack, etc) that 
supports this.


--Iggy


On 7/2/2014 10:17 AM, yue wrote:

hi,all
i now look at qemu 2.0, i do not find rbd-api related to clone.
if qemu support this function? and from which version?
clone api of rbd is very simple(one api), why qemu does not
implement?what is the reason?
thanks.

Re: [Qemu-devel] from which version qemu support clone on rbd

[yue]

could you tell me why 'Qemu doesn't handle that level of abstraction'?
i know qcow2 well, you can tell me the comparation。
 
thanks







At 2014-07-02 11:36:12, Brian Jackson i...@theiggy.com wrote:
Qemu doesn't handle that level of abstraction. The closest approximation 
you could probably come up with is qemu-img's backing file support for 
qcow2 images.

You should stick to using the rbd tool to create clones of rbd devices. 
Alternatively, use a higher level tool (like openstack, etc) that 
supports this.

--Iggy


On 7/2/2014 10:17 AM, yue wrote:
 hi,all
 i now look at qemu 2.0, i do not find rbd-api related to clone.
 if qemu support this function? and from which version?
 clone api of rbd is very simple(one api), why qemu does not
 implement?what is the reason?
 thanks.

Re: [Qemu-devel] from which version qemu support clone on rbd

[Brian Jackson]

On Wednesday, July 2, 2014 8:12:17 PM CDT, yue wrote:

could you tell me why 'Qemu doesn't handle that level of abstraction'?
i know qcow2 well, you can tell me the comparation。



Qemu would have to have a lot of extra code (that already exists elsewhere) 
to support taking snapshots/clones/etc of every backend device it supports. 
In the case of qcow2, the support exists because of the whole system 
snapshotting feature. Otherwise it's bloat that Qemu doesn't normally 
handle (it's left to the management layers above to handle).


--Iggy


 
thanks








At 2014-07-02 11:36:12, Brian Jackson i...@theiggy.com wrote:
Qemu doesn't handle that level of abstraction. The closest approximation 
you could probably come up with is qemu-img's backing file support for 
qcow2 images.


You should stick to using the rbd tool to create clones of rbd devices. 
Alternatively, use a higher level tool (like openstack, etc) that  ...